Cellular determinants of metabolite concentration ranges.

Cellular functions are shaped by reaction networks whose dynamics are determined by the concentrations of underlying components. However, cellular mechanisms ensuring that a component's concentration resides in a given range remain elusive. We present network properties which suffice to identify components whose concentration ranges can be efficiently computed in mass-action metabolic networks.

Advances in metabolic flux analysis toward genome-scale profiling of higher organisms.

Methodological and technological advances have recently paved the way for metabolic flux profiling in higher organisms, like plants. However, in comparison with omics technologies, flux profiling has yet to provide comprehensive differential flux maps at a genome-scale and in different cell types, tissues, and organs. Here we highlight the recent advances in technologies to gather metabolic labeling patterns and flux profiling approaches.

A efflux pump acts on short-chain alcohols.

Background: The microbial production of biofuels is complicated by a tradeoff between yield and toxicity of many fuels. Efflux pumps enable bacteria to tolerate toxic substances by their removal from the cells while bypassing the periplasm. Their use for the microbial production of biofuels can help to improve cell survival, product recovery, and productivity.

Near-Falls in Elderly Community-Dwelling Blacks From Two Out-Patient Clinics in Harlem.

Background: Near-falls are a frequent, but not commonly studied, occurrence in the elderly Black population and may be related to prospective falls.

Objectives: The purpose of this paper is to examine the relationship of near-falls to demographic characteristics, use of assistive devices, gait, and physical activity levels in elderly Blacks.

Methods: Community-dwelling, elderly Black patients aging 65 and older and attending two clinics of the Mount Sinai Hospital in Harlem in New York City were recruited.

A network property necessary for concentration robustness.

Maintenance of functionality of complex cellular networks and entire organisms exposed to environmental perturbations often depends on concentration robustness of the underlying components. Yet, the reasons and consequences of concentration robustness in large-scale cellular networks remain largely unknown. Here, we derive a necessary condition for concentration robustness based only on the structure of networks endowed with mass action kinetics.