Human pluripotency: A difficult state to make smart choices

Comment on: Hong SH, et al. Cell Stem Cell 2011; 9:24-36.     

Behavioral choices: how neuronal networks make decisions

To survive, animals must constantly make behavioral choices. The analysis of simple, almost binary, behavioral choices in invertebrate animals with restricted nervous systems is beginning to yield insight into how neuronal networks make such decisions.     

A life cycle environmental sustainability analysis of microbial protein production via power-to-food approaches

The International Journal of Life Cycle Assessment - Renewable energy produced from wind turbines and solar photovoltaics (PV) has rapidly increased its share in global energy markets. At the same...     

A framework for quantifying environmental sustainability

Recent concepts of environmental sustainability have focused on narrative economic and societal aspects rather than quantitative ones. Many key sustainability indicators also lack a consistent definition of sustainability, have perspectives that are too short-term, and are unable to model the dynamics of complex environmental utilization which can then result in inappropriate projection of long-term sustainability and/or sustainability indication. Here I propose a generalized quantitative framework of environmental sustainability requiring that (1) environmental capacities and utilization rates are identified, (2) their complex temporal dynamics are quantitatively modeled or estimated (3) while also adjusting for uncertainties, and finally, (4) using one of three options, determining which cumulative utilization pathways can be sustained for a (usually well-defined) period of time. Using the example of wood volume and its growth as capacities and harvest as utilization, and the example of global greenhouse gas emissions as the utilization component and the capacity of the air to absorb these emissions, I demonstrate how the proposed framework can be applied in practice, how sustainability indicators could be developed, and also how they can inform policies and measures to ensure sustainability.     

Appropriate technologies for environmental hygiene

Appropriate technologies for environmental hygiene usually centre on the delivery of adequate and accessible water supply, and proper treatment and disposal of excreta and refuse. In the face of the International Drinking Water and Sanitation Decade of 1981-90, several research efforts are under way in the developing countries to develop technologies and approaches for improving environmental hygiene in both rural areas and urban squatter settlements. These are discussed and include the technical development and field testing of infiltration galleries, low-cost slow and fast filtration processes for water treatment, handpumps, on-site excreta disposal using aqua-privy and compost toilets, and excreta treatment and refuse through composting with refuse, biogas generation, fish culture and use of excreta as crop fertilizer. The relevant technology 'hardware' is but one of several components necessary for effective delivery of services. The dearth of qualified manpower at all levels is described as being the major constraint to the Water and Sanitation Decade.     

Indicators to support environmental sustainability of bioenergy systems

Indicators are needed to assess environmental sustainability of bioenergy systems. Effective indicators will help in the quantification of benefits and costs of bioenergy options and resource uses. We identify 19 measurable indicators for soil quality, water quality and quantity, greenhouse gases, biodiversity, air quality, and productivity, building on existing knowledge and on national and international programs that are seeking ways to assess sustainable bioenergy. Together, this suite of indicators is hypothesized to reflect major environmental effects of diverse feedstocks, management practices, and post-production processes. The importance of each indicator is identified. Future research relating to this indicator suite is discussed, including field testing, target establishment, and application to particular bioenergy systems. Coupled with such efforts, we envision that this indicator suite can serve as a basis for the practical evaluation of environmental sustainability in a variety of bioenergy systems.     

Metabolic reengineering invoked by microbial systems to decontaminate aluminum: Implications for bioremediation technologies

As our reliance on aluminum (Al) increases, so too does its presence in the environment and living systems. Although generally recognized as safe, its interactions with most living systems have been nefarious. This review presents an overview of the noxious effects of Al and how a subset of microbes can rework their metabolic pathways in order to survive an Al-contaminated environment. For instance, in order to expulse the metal as an insoluble precipitate, Pseudomonas fluorescens shuttles metabolites toward the production of organic acids and lipids that play key roles in chelating, immobilizing and exuding Al. Further, the reconfiguration of metabolic modules enables the microorganism to combat the dearth of iron (Fe) and the excess of reactive oxygen species (ROS) promoted by Al toxicity. While in Rhizobium spp., exopolysaccharides have been invoked to sequester this metal, an ATPase is known to safeguard Anoxybacillus gonensis against the trivalent metal. Hydroxyl, carboxyl and phosphate moieties have also been exploited by microbes to trap Al. Hence, an understanding of the metabolic networks that are operative in microorganisms residing in polluted environments is critical in devising bioremediation technologies aimed at managing metal wastes. Metabolic engineering is essential in elaborating effective biotechnological processes to decontaminate metal-polluted surroundings.     

Harnessing microbial activities for environmental cleanup

Human activities have released large amounts of toxic organic and inorganic chemicals into the environment. Toxic waste streams threaten dwindling drinking water supplies and impact terrestrial, estuarine and marine ecosystems. Cleanup is technically challenging and the costs based on traditional technologies are exceeding the economic capabilities of even the richest countries. Recent advances in our understanding of the microbiology contributing to contaminant transformation and detoxification has led to successful field demonstrations. Hence, harnessing the activity of naturally occurring bacteria, particularly the power of anaerobic reductive processes, is a promising approach to restore contaminated subsurface environments, protect drinking water reservoirs and to safeguard ecosystem health.     

Next-generation sequencing technologies for environmental DNA research

Since 2005, advances in next-generation sequencing technologies have revolutionized biological science. The analysis of environmental DNA through the use of specific gene markers such as species-specific DNA barcodes has been a key application of next-generation sequencing technologies in ecological and environmental research. Access to parallel, massive amounts of sequencing data, as well as subsequent improvements in read length and throughput of different sequencing platforms, is leading to a better representation of sample diversity at a reasonable cost. New technologies are being developed rapidly and have the potential to dramatically accelerate ecological and environmental research. The fast pace of development and improvements in next-generation sequencing technologies can reflect on broader and more robust applications in environmental DNA research. Here, we review the advantages and limitations of current next-generation sequencing technologies in regard to their application for environmental DNA analysis.     

Response of microbial populations to environmental disturbance

Taxonomic and genetic diversities of microbial communities disturbed by chemical pollutants were lower than in undisturbed reference communities. The dominant populations within the disturbed communities had enhanced physiological tolerances and substrate utilization capabilities, indicating that generalized physiological versatility is an adaptive characteristic of populations that successfully compete within disturbed communities.     

Exploiting antibody-based technologies to manage environmental pollution.

Many commodities used in the food, cosmetic, chemical and environmental industrial sectors function by binding to other molecules. Antibodies can bind virtually any molecule, from large proteins to small organic ligands, and could replace substances with undesirable medical, social or environmental side effects, if they could be provided in stable configurations and in quantities and at costs acceptable to industry. Antibody fragments also offer the possibility of sensitive detection and efficient removal of organic pollutants from the environment.     

Inter-generational equity index for assessing environmental sustainability: An example on global warming

Inter-generational equity is essential for environmental sustainability. The current generation inherits an environment with a certain quality from the previous generation. The impact on the environment gradually exacerbates and accumulates over a period of time between two generations. However, currently there is no index available to assess inter-generational equity. Generally a typical environmental index is established to represent the environmental status in a specific year. This kind of index, although it presents the annual environmental variation, does not reflect the degree of change in environmental sustainability between two generations. Therefore, an inter-generational equity index (IGEI) and an endowment equation to examine the temporal trend of the changing environment are proposed for assessing inter-generational equity. To demonstrate the applicability of the endowment equation, an IGEI was established to assess the inter-generational equity of global warming. The global warming IGEI evaluates the status between two generations based on three sub-indexes; CO₂ emission, loss due to climate disasters, and the size of the existing forest area. The pressure–state–response (PSR) framework was adopted to explain the causal relationship between these three sub-indexes. According to the endowment rate determined by the proposed equation for each sub-index, the increase in CO₂ emission from 1980 to 2000 shows an obviously inequitable pattern between generations. Subsequently, the loss due to climate disasters between generations was also more serious. The size of the forest area, an important factor for reducing the impact of global warming, is unfortunately also decreasing significantly between generations. Using the endowment rate determined by the proposed endowment equation, the evaluation of the inter-generational equity is made possible and is demonstrated by the IGEI established for global warming.     

Poor environmental tracking can make extinction risk insensitive to the colour of environmental noise

The relative importance of environmental colour for extinction risk compared with other aspects of environmental noise (mean and interannual variability) is poorly understood. Such knowledge is currently relevant, as climate change can cause the mean, variability and temporal autocorrelation of environmental variables to change. Here, we predict that the extinction risk of a shorebird population increases with the colour of a key environmental variable: winter temperature. However, the effect is weak compared with the impact of changes in the mean and interannual variability of temperature. Extinction risk was largely insensitive to noise colour, because demographic rates are poor in tracking the colour of the environment. We show that three mechanisms-which probably act in many species-can cause poor environmental tracking: (i) demographic rates that depend nonlinearly on environmental variables filter the noise colour, (ii) demographic rates typically depend on several environmental signals that do not change colour synchronously, and (iii) demographic stochasticity whitens the colour of demographic rates at low population size. We argue that the common practice of assuming perfect environmental tracking may result in overemphasizing the importance of noise colour for extinction risk. Consequently, ignoring environmental autocorrelation in population viability analysis could be less problematic than generally thought.     

Global environmental impacts: data sources and methodological choices for calculating normalization factors for LCA

The International Journal of Life Cycle Assessment - Characterizing environmental impacts at the global scale is crucial to define references against which compare the environmental profile of...