Ecological hazard/risk assessment: lessons learned and new directions

A series of workshops held in the 1970s and 1980s, beginning at the University of Michigan Biological Station near Pellston, Michigan (and thus called the Pellston Series), focused on identifying the basic tenets of ecological hazard/risk assessment. The purpose of this discussion, produced roughly two decades after the first Pellston workshop, is to examine the impacts of this series on the development of the ecological hazard/risk assessment process, to explore some barriers hindering the development of this process, and suggest some new directions and challenges yet unaddressed by any of the workshop series. Probably the most important factor identified since the series of workshops began is persuasive circumstantial evidence that the learning process proceeds at different rates for individuals and institutions both in the government and private sectors, including academe. Evidence presently available suggests that individuals are frequently two or three decades ahead of institutions, and some individuals have already rejected paradigms generally accepted by the profession and are developing new ones. The major contribution of the workshops to the profession was connecting toxicity with environmental fate and transformation of chemicals and thus, bioavailability. Astonishingly, before the first Pellston workshop, this now-obvious connection did not play a dominant role in the peer-reviewed professional literature or in government documents, although the indefatigable investigator could find some minor indications that some professionals were aware of the importance of these relationships. Major suggestions for new directions and challenges focus on: (1) an emphasis on ecosystem health or condition rather than on mere absence of deleterious effects; (2) entering the information age requires that the type of information discussed here be integrated with and related to the broader array of other types of information used in making decisions at the societal or system level — failure to do so will mean that hazard/risk information will have little or no impact; (3) restoration ecology must emerge as a field of considerable importance because inevitably some estimates of hazard/risk will be inaccurate and damage will be done to ecosystems, which must then be repaired; (4) for all of this to function, environmental literacy must be markedly improved over its present level.     

Genes invading new populations: a risk assessment perspective

One of the concerns raised over the introduction of genetically modified crops is that transgenes will invade populations of wild relatives, causing ecologically significant changes in fitness. In recent years, this has given rise to several studies estimating hybridization rates and the fitness of crop-wild relative hybrids. These studies have established that transgenes are likely to move to F1 hybrids, albeit at low frequency. Hybridization, however, is not synonymous with introgression, and questions remain as to whether particular transgenes will cause ecologically significant changes in recipient plant populations. Research effort should now focus on estimating any changes in the fitness of a population as a consequence of having a transgene, understanding genotype x environment interactions, and deducing the extent to which pathogens and herbivores (transgene targets) regulate wild relative populations. This will involve a combination of manipulative experiments and empirically motivated mathematical models.     

Xenopus oocyte maturation: new lessons from a good egg.

Fully grown Xenopus oocytes can remain in their immature state essentially indefinitely, or, in response to the steroid hormone progesterone, can be induced to develop into fertilizable eggs. This process is termed oocyte maturation. Oocyte maturation is initiated by a novel plasma membrane steroid hormone receptor. Progesterone brings about inhibition of adenylate cyclase and activation of the Mos/MEK1/p42 MAP kinase cascade, which ultimately brings about the activation of the universal M phase trigger Cdc2/cyclin B. Oocyte maturation provides an interesting example of how signaling cascades entrain the cell cycle clock to environmental changes.     

Wildlife control,access and utilisation: Lessons from legislation,policy evolution and implementation in Zimbabwe

This paper retraces: (1) the promulgation of protectionist wildlife policies by colonial administrators at the turn of the 19th Century in Zimbabwe, and their evolutionary trajectory over distinct time periods, (2) the paradigmatic shift and the extent of evolution of wildlife policies with respect to the devolution thrust and local community participation to date. The aim is to re-ignite and keep alive the debate for the improvement of local community livelihoods by meeting their aspirations and addressing poverty. Another section explores the robustness of local community institutional framework following decades of research on their efficacy in the face of internal weaknesses and external pressures. This is discussed in the context of contested devolution and decentralisation concepts which not in the distant past became fashionable rhetoric in the field of local community empowerment in natural resource management. Areas of contests have been explored using a case study approach. Extensive literature consultation and gleaning of 127 published and relevant sources cutting across national, regional and global realms reveal that Zimbabwe and most southern African countries have evolved progressive policies. However, consistent with most literature, the implementation of these otherwise progressive policies remains problematic. Hence, the question, ‘when will community-based wildlife conservation initiatives like communal areas management programme for indigenous resources (CAMPFIRE) achieve their initially intended goals of devolution?’ remains largely unaddressed.     

Engineering new metabolic capabilities in bacteria: lessons from recombinant cellulolytic strategies

Cellulose waste biomass is the most attractive substrate for 'biorefinery strategies' producing high-value products (e.g. fuels or plastics) by fermentation. However, traditional biomass bioconversions are economically inefficient multistep processes. Thus far, no microorganisms able to perform single-step fermentation into products (consolidated bioprocessing; CBP) have been isolated. Metabolic engineering is currently employed to develop recombinant microorganisms suitable for CBP. The heterologous expression of extracellular proteins (e.g. cellulases or hemicellulases) is the key feature of recombinant cellulolytic strategies, conferring cellulolytic ability to microorganisms exhibiting high product yields and titers. Although more molecular tools are becoming available, efficient heterologous expression of secreted proteins is still a challenge. The present review summarizes both bottlenecks and solutions of organism engineering for biomass biorefinery strategies.     

Hibernation in the tropics: lessons from a primate

The Malagasy primate Cheirogaleus medius hibernates in tree holes for 7 months, although ambient temperatures during hibernation rise above 30°C in their natural environment. In a field study we show that during hibernation the body temperature of most lemurs fluctuates between about 10°C and 30°C, closely tracking the diurnal fluctuations of ambient temperature passively. These lemurs do not interrupt hibernation by spontaneous arousals, previously thought to be obligatory for all mammalian hibernators. However, some lemurs hibernate in large trees, which provide better thermal insulation. Their body temperature fluctuates only little around 25°C, but they show regular arousals, as known from temperate and arctic hibernators. The results from this study demonstrate that maximum body temperature is a key factor necessitating the occurrence of arousals. Furthermore, we show that hibernation is not necessarily coupled to low body temperature and, therefore, low body temperature should no longer be included in the definition of hibernation.     

Genetic risk factors in tumours of the testis: lessons from twin studies.

A threefold increase for testicular carcinoma has been reported in male dizygotic twins. In this comment we suggest the hypothesis that over-exposure to endogenously hypersecreted Follicle Stimulating Hormone (FSH) may underlie the pathogenesis. This is supported by several findings. 1) FSH hypersecretion in mothers of dizygotic twins is most likely an autosomal trait implicating the possibility of male offspring with the same hormone characteristic. 2) In testicular carcinoma higher levels of cyclin D2 are found. This is an FSH dependent stimulatory regulator of mitosis. 3) There is a marked similarity between geographical distribution in occurence of dizygotic twinning and testicular carcinoma. 4) Men undergoing surgery for testicular carcinoma have higher FSH concentrations and males with Down syndrome have higher FSH levels and are more at risk to develop testicular carcinoma. We suggest to study FSH secretion in males of familial dizygotic twins and furthermore the risk of developing testicular carcinoma in males with elevated FSH. These men with one testicle and/or with dysfunctioning Sertoli/Leydig cells.     

Progress in sustainability science: lessons learnt from current methodologies for sustainability assessment: Part 1

Purpose

Sustainability Science (SS) is considered an emerging discipline, applicative and solution-oriented whose aim is to handle environmental, social and economic issues in light of cultural, historic and institutional perspectives. The challenges of the discipline are not only related to better identifying the problems affecting sustainability but to the actual transition towards solutions adopting an integrated, comprehensive and participatory approach. This requires the definition of a common scientific paradigm in which integration and interaction amongst sectorial disciplines is of paramount relevance. In this context, life cycle thinking (LCT) and, in particular, life cycle-based methodologies and life cycle sustainability assessment (LCSA) may play a crucial role. The paper illustrates the main challenges posed to sustainability assessment methodologies and related methods in terms of ontology, epistemology and methodology of SS. The aims of the analysis are twofold: (1) to identify the main features of methodologies for sustainability assessment and (2) to present key aspects for the development of robust and comprehensive sustainability assessment.

Methods

The current debate on SS addressing ontological, epistemological and methodological aspects has been reviewed, leading to the proposal of a conceptual framework for SS. In addition, a meta-review of recent studies on sustainability assessment methodologies and methods, focusing those life cycle based, supports the discussion on the main challenges for a comprehensive and robust approach to sustainability assessment. Starting from the results of the meta-review, we identified specific features of sustainable development-oriented methods: firstly, highlighting key issues towards robust methods for SS and, secondly, capitalising on the findings of each review’s paper. For each issue, a recommendation towards a robust sustainability assessment method is given. Existing limitations of sectorial academic inquiries and proposal for better integration and mainstreaming of SS are the key points under discussion.

Discussion

In the reviewed papers, LCT and its basic principles are acknowledged as relevant for sustainability assessment. Nevertheless, LCT is not considered as a reference approach in which other methods could also find a place. This aspect has to be further explored, addressing the lack of multi-disciplinary exchange and putting the mainstreaming of LCT as a priority on the agenda of both life cycle assessment and sustainability assessment experts. Crucial issues for further developing sustainability assessment methodologies and methods have been identified and can be summarised as follows: holistic and system wide approaches, shift from multi- towards trans-disciplinarity; multi-scale (temporal and geographical) perspectives; and better involvement and participation of stakeholders.

Conclusions

Those are also the main challenges posed to LCSA in terms of progress of ontology, epistemology and methodology in line with the progress of SS. The life cycle-based methodologies should be broadened from comparing alternatives and avoiding negative impacts, to also proactively enhancing positive impacts, and towards the achievement of sustainability goals.     

Fear in animals: a meta-analysis and review of risk assessment

The amount of risk animals perceive in a given circumstance (i.e. their degree of 'fear') is a difficult motivational state to study. While many studies have used flight initiation distance as a proxy for fearfulness and examined the factors influencing the decision to flee, there is no general understanding of the relative importance of these factors. By identifying factors with large effect sizes, we can determine whether anti-predator strategies reduce fear, and we gain a unique perspective on the coevolution of predator and anti-predator behaviour. Based on an extensive review and formal meta-analysis, we found that predator traits that were associated with greater risk (speed, size, directness of approach), increased prey distance to refuge and experience with predators consistently amplified the perception of risk (in terms of flight initiation distance). While fish tolerated closer approach when in larger schools, other taxa had greater flight initiation distances when in larger groups. The presence of armoured and cryptic morphologies decreased perception of risk, but body temperature in lizards had no robust effect on flight initiation distance. We find that selection generally acts on prey to be sensitive to predator behaviour, as well as on prey to modify their behaviour and morphology.     

Assessing the biosecurity risk from pathogens and herbivores to indigenous plants: lessons from weed biological control

Some potentially invasive herbivores/pathogens in their home range may attack plants originating from another geographic area. Methods are required to assess the risk these herbivores/pathogens pose to these plants in their indigenous ecosystems. The processes and criteria used by weed biological control researchers to assess the impact of potential biological control agents on a plant species in its non-native range provide a possible framework for assessing risks to indigenous plants. While there are similarities between these criteria such as the need for clear objectives, studies in the native range of the herbivore/pathogen, good knowledge of the ecology of the target plant and taxonomy of the plant and herbivore/pathogen, and modelling of the interaction between the two organisms, there are some important differences in approach. These include the need to consider the threat classification of the plant, the likely greater risk from polyphagous herbivores/pathogens than oligophagous or monophagous species, and the need to consider the impact of an additional natural enemy in conjunction with a suite of existing natural enemies. The costs of conducting a risk assessment of a herbivore/pathogen in another country that damages plants indigenous to another geographic area means that criteria will be needed for deciding which foreign herbivore/pathogen species should be assessed. These criteria could include the threat classification of the plant, the amount of damage to the particular plant organs affected, and the importance in key ecosystems.     

DNA-expressed human cytochrome P450s: a new age of molecular toxicology and human risk assessment

It has long been recognized that a large degree of species differences exists among drug and carcinogen metabolizing enzymes. In particular, differences in cytochrome P450s, the principal enzymes of metabolic activation of procarcinogens, are widespread and may determine species and individual susceptibility to cancer causing chemicals. Although species differences in both the regulation and catalytic activities of P450s are quite large, roden-based systems are mainly used as the means to determine the degree of hazard of environmental pollutants, pesticides, drugs and other environmental chemicals to humans. During recent years, a large effort has been expended on analyzing directly the structure, properties and catalytic activities of P450s from human tissues. In vitro mutagen testing systems, based on activation by human P450s, are being developed that will supplement other test systems in order to more accurately predict human risk to chemical exposure.     

Population prevalence of hereditary breast cancer phenotypes and implementation of a genetic cancer risk assessment program in southern Brazil

In 2004, a population-based cohort (the Núcleo Mama Porto Alegre - NMPOA Cohort) was started in Porto Alegre, southern Brazil and within that cohort, a hereditary breast cancer study was initiated, aiming to determine the prevalence of hereditary breast cancer phenotypes and evaluate acceptance of a genetic cancer risk assessment (GCRA) program. Women from that cohort who reported a positive family history of cancer were referred to GCRA. Of the 9218 women enrolled, 1286 (13.9%) reported a family history of cancer. Of the 902 women who attended GCRA, 55 (8%) had an estimated lifetime risk of breast cancer ≥ 20% and 214 (23.7%) had pedigrees suggestive of a breast cancer predisposition syndrome; an unexpectedly high number of these fulfilled criteria for Li-Fraumeni-like syndrome (122 families, 66.7%). The overall prevalence of a hereditary breast cancer phenotype was 6.2% (95%CI: 5.67-6.65). These findings identified a problem of significant magnitude in the region and indicate that genetic cancer risk evaluation should be undertaken in a considerable proportion of the women from this community. The large proportion of women who attended GCRA (72.3%) indicates that the program was well-accepted by the community, regardless of the potential cultural, economic and social barriers.     

Trends in childbearing and stillbirth risk: heterogeneity among Italian regions

In Italy, as in all Western countries, the almost monotonic decline in fertility observed since the 1960s has been paralleled until the beginning of the 1980s by a decrease in maternal age at delivery. Since then, age at marriage and at childbearing has been increasing and marital fertility has continued to decrease. By 1994 Italy showed extreme values of low total fertility rate (1.22) and of high mean maternal age at delivery (29.7). For the period between 1960 and 1994 we identified five U-shaped patterns in maternal age at delivery corresponding to five geographical areas, which differ socioeconomically and culturally. Since it is well known that an increase in the maternal age is accompanied by an increase in the risk of unfavorable pregnancy outcome, we estimated the stillbirth risk run by older (> or =35 years) mothers who delivered in 1994, with respect to their younger counterparts. The differences between the areas are reflected in the higher risk in southern compared to northern Italy: the maximum value occurred in Sicily (odds ratio 2.02, 95% confidence interval, 1.51-2.70) and the minimum value, even lower than in the north but not statistically significant, was found in Sardinia (odds ratio 1.25, 95% confidence interval, 0.81-1.91), known to be characterized by peculiar cultural and biological features.     

Small GTPases in Dictyostelium: lessons from a social amoeba

Although the process of sequencing the Dictyostelium genome is not complete, it is already producing surprises, including an unexpectedly large number of Ras- and Rho-subfamily GTPases. Members of these families control a wide variety of cellular processes in eukaryotes, including proliferation, differentiation, cell motility and cell polarity. Comparison of small GTPases from Dictyostelium with those from higher eukaryotes provides an intriguing view of their cellular and evolutionary roles. In particular, although mammalian Ras proteins interact with several signalling pathways, the Dictyostelium pathways appear more linear, with each Ras apparently performing a specific cellular function.     

Pathogenic idiotypes of autoantibodies in autoimmunity: lessons from new experimental models of SLE

Systemic lupus erythematosus (SLE) is considered a classical autoimmune disease that involves many biological systems. Similar to other autoimmune conditions, its etiology is multifactorial entailing genetic, environmental, hormonal, and immunologic factors. In this review we demonstrate that by using a pathogenic idiotype of anti-DNA autoantibodies, it is possible to explain some of the pathogenesis and diversity of clinical and serological manifestations reported by SLE patients. The 16/6 idiotype (Id) is a representative pathogenic idiotype of anti-DNA autoantibodies. The serum titers of 16/6 Id in SLE patients correlate with clinical activity of the disease, and are deposited in afflicted tissues in SLE patients. SLE was experimentally induced in naive mice after immunization with 1 microgram of the Id. The disease is characterized clinically (proteinuria), serologically (e.g., anti-dsDNA, anti-Sm antibodies), and by pathological findings (e.g., deposition of 16/6 Id in the kidneys). The condition can be induced by other human and mouse antibodies carrying the 16/6 Id, as well as by mouse antimonoclonal-16/6 Id and by T cell lines and clones specifically reactive with 16/6 Id. There are strain-dependent differences in susceptibility to the induction of systemic lupus erythematosus (SLE). Induction of SLE is directly correlated with the ability to respond to the 16/6 idiotype (or 16/6 Id)2 by anti-Id antibody production. It is easier to induce the disease in females, and it can be modulated by manipulation of sex hormones. Being able to identify the pathogenic idiotype allowed us to generate T suppressor (Ts) cells specific for the 16/6 Id. Treatment of mice with these T cells abrogated the disease. Our studies point to the importance of pathogenic idiotypes of autoantibodies in autoimmunity, which suggests that SLE may represent a dysregulation of a functional network of idiotypes-anti-idiotypes interactions among autoreactive B cells, T helper cells, and T suppressor cells.