Developmental models for estimating ecological responses to environmental variability: structural, parametric, and experimental issues.

Developmental models that account for the metabolic effect of temperature variability on poikilotherms, such as degree-day models, have been widely used to study organism emergence, range and development, particularly in agricultural and vector-borne disease contexts. Though simple and easy to use, structural and parametric issues can influence the outputs of such models, often substantially. Because the underlying assumptions and limitations of these models have rarely been considered, this paper reviews the structural, parametric, and experimental issues that arise when using degree-day models, including the implications of particular structural or parametric choices, as well as assumptions that underlie commonly used models.

Systematic quantification of developmental phenotypes at single-cell resolution during embryogenesis.

Current imaging technology provides an experimental platform in which complex developmental processes can be observed at cellular resolution over an extended time frame. New computational tools are essential to achieve a systems-level understanding of this high-content information. We have devised a structured approach to systematically analyze complex in vivo phenotypes at cellular resolution, which divides the task into a panel of statistical measurements of each cell in terms of cell differentiation, proliferation and morphogenesis, followed by their spatial and temporal organization in groups and the cohesion within the whole specimen.

Cautioning the use of degree-day models for climate change projections in the presence of parametric uncertainty.

Developmental models, such as degree-day models, are commonly used to predict the impact of future climate change on the intensity, distribution, and timing of the transmission of infectious diseases, particularly those caused by pathogens carried by vectors or intermediate hosts. Resulting projections can be useful in policy discussions concerning regional or national responses to future distributions of important infectious diseases. Although the simplicity of degree-day models is appealing, little work has been done to analyze their ability to make reliable projections of the distribution of important pathogens, vectors, or intermediate hosts in the presence of the often considerable parametric uncertainty common to such models.

Actomyosin-based self-organization of cell internalization during C. elegans gastrulation.

Background: Gastrulation is a key transition in embryogenesis; it requires self-organized cellular coordination, which has to be both robust to allow efficient development and plastic to provide adaptability. Despite the conservation of gastrulation as a key event in Metazoan embryogenesis, the morphogenetic mechanisms of self-organization (how global order or coordination can arise from local interactions) are poorly understood.

Results: We report a modular structure of cell internalization in Caenorhabditis elegans gastrulation that reveals mechanisms of self-organization.

Magnetic resonance imaging characteristics of glioblastoma multiforme: implications for understanding glioma ontogeny.

Background: Identifying the origin of gliomas carries important implications for advancing the treatment of these recalcitrant tumors. Recent research promotes the hypothesis of a subventricular zone (SVZ) origin for the stemlike gliomagenic cells identified within human glioma specimens. However, conflicting evidence suggests that SVZ-like cells are not uniquely gliomagenic but this capacity may be shared by cycling progenitors distributed throughout the subcortical white matter (SCWM).