The crystal structure of rod cell visual pigment rhodopsin was recently solved at 2.8-A resolution. A critical evaluation of a decade of structure-function studies is now possible. It is also possible to begin to explain the structural basis for several unique physiological properties of the vertebrate visual system, including extremely low dark noise levels as well as high gain and color detec...

Renal proximal tubules secrete various organic anions, including drugs and p-aminohippurate (PAH). Uptake of PAH from blood into tubule cells occurs by exchange with intracellular alpha-ketoglutarate and is mediated by the organic anion transporter 1. PAH exit into tubule lumen is species specific and may involve ATP-independent and -dependent transporters.

Petal senescence is reviewed, with the main emphasis on gene expression in relation to physiological functions. Autophagy seems to be the major mechanism for large-scale degradation of macromolecules, but it is still unclear if it contributes to cell death. Depending on the species, petal senescence is controlled by ethylene or is independent of this hormone. EIN3-like (EIL) transcription facto...

Two types of cells, osteoblasts and osteoclasts, maintain bone homeostasis by balancing each other’s function [1,2]. Osteoblasts, which build bone, are derived from a mesenchymal progenitor cell that can also differentiate into marrow stromal cells and adipocytes [3]. Osteoclasts, originating from hemopoietic progenitors of the monocyte/macrophage lineage, immigrate into bone via the blood stre...

Cyanobacteria thrive in every illuminated aquatic environment known, contributing at least 25% of primary productivity worldwide. Given their importance in carbon and nutrient cycles, cyanobacteria are essential geochemical agents that have shaped the composition of the Earth’s crust, oceans and atmosphere for billions of years. The high diversity of cyanobacteria is reflected in the panoply of...

Adult skeletal muscle has a remarkable ability to regenerate following myotrauma. Because adult myofibers are terminally differentiated, the regeneration of skeletal muscle is largely dependent on a small population of resident cells termed satellite cells. Although this population of cells was identified 40 years ago, little is known regarding the molecular phenotype or regulation of the satel...

Physiological adaptation to acute hypoxia involves oxygen-sensing by a variety of specialized cells including carotid body type I cells, pulmonary neuroepithelial body cells, pulmonary artery myocytes and foetal adrenomedullary chromaffin cells. Hypoxia induces depolarization by closing a specific set of potassium channels and triggers cellular responses. Molecular biology strategies have recen...

The respiratory muscles have been studied extensively during the last 20 yrs. This interest was triggered predominantly by the observation made by ROUSSOS and MACKLEM [1] that the respiratory muscles, like all other skeletal muscles, may fatigue. Subsequent research critically examined the significance of inspiratory muscle fatigue in clinical pulmonary medicine. The conclusion of this research...

Recent advances in molecular biology have identified three organic anion transporter families: the organic anion transporter (OAT) family encoded by SLC22A, the organic anion transporting peptide (OATP) family encoded by SLC21A (SLCO), and the multidrug resistance-associated protein (MRP) family encoded by ABCC. These families play critical roles in the transepithelial transport of organic anio...

Respiratory physiology is under threat. What was once regarded as the science underpinning respiratory medicine is now being eroded by a move towards cell and molecular biology that threatens its very existence. This trend is not confined to the respiratory field, but is also occurring in most other specialities. Some academic departments of respiratory physiology and research groups in physiol...