Osmoregulation
Ian Kay in Introduction to Animal Physiology, 2020
This chapter looks at the osmoregulatory functions of animal. The ability to regulate water and solute concentrations is referred to as osmoregulation. It is necessary to review the concept of osmosis as this is central to the process of osmoregulation. Osmosis is an example of a colligative property. When animal cells are placed in distilled water, the cell rapidly gains water by osmosis and will eventually burst. Equally, if cells are placed in a concentrated salt solution, they will rapidly lose water by osmosis and will shrink. It is possible to classify the osmotic responses of animals into two broad categories — they are either osmoconformers or osmoregulators. Osmoconformers are animals whose body fluid concentration is exactly the same as that of the immediate environment in which they live. The osmotic and ionic conformation that the hagfish utilizes has been used as physiological evidence that vertebrates evolved in the marine environment.
Metabolic Regulation in Response to Growth Environment
Kazuyuki Shimizu in Metabolic Regulation and Metabolic Engineering for Biofuel and Biochemical Production, 2017
Living organisms have sophisticated but well organized regulation system. It is important to understand the metabolic regulation mechanisms in relation to growth environment for the efficient design of cell factories for biofuel and biochemical production. This chapter provides an overview for nitrogen regulation, ion, sulfur, and phosphate regulations, stringent response under nutrient starvation as well as oxidative stress regulation, redox regulation, acid shock, heat and cold shock regulations, solvent stress regulation, osmoregulation, as well as biofilm formation and quorum sensing. The coordinated regulation mechanisms are of particular interest in getting insight into the principle which governs the cell metabolism. Moreover, multiple regulations are coordinated by the intracellular metabolites, where fructose 1,6-bisphosphate, phosphoenol pyruvate, and acetyl CoA play important roles for enzyme level regulation for the coordinated regulation between carbon source uptake rate and other nutrient uptake rate such as nitrogen or sulfur uptake rate by modulation of cAMP via Cya.
Metals in Biology
Raul Sutton in Chemistry for the Life Sciences, 2009
Metals form an important component of all cellular organisms. Nearly all of the metal in living organisms is in the ion form, either bound to biomolecules or free in solution. Metal is bound via ionic or co-ordinate bonds, and metal ions in solution are often part of complexes. Metals can be divided into two broad classes: the alkali or alkali earth metals and the transition metals. Other metals, such as selenium, also play a minor role in living organisms. Metals have a wide variety of functions within living systems, including osmoregulator, structural component of tissues such as bone, protein or enzyme cofactor, and redox or electrical charge carrier. Many metals are toxic to living systems, and even some essential metals are toxic if dietary intake is exceeded.
Shaping up for action
Published in Organogenesis, 2013
The Malpighian tubule is the main organ for excretion and osmoregulation in most insects. During a short period of embryonic development the tubules of Drosophila are shaped, undergo differentiation and become precisely positioned in the body cavity, so they become fully functional at the time of larval hatching a few hours later. In this review I explore three developmental events on the path to physiological maturation. First, I examine the molecular and cellular mechanisms that generate organ shape, focusing on the process of cell intercalation that drives tubule elongation, the roles of the cytoskeleton, the extracellular matrix and how intercalation is coordinated at the tissue level. Second, I look at the genetic networks that control the physiological differentiation of tubule cells and consider how distinctive physiological domains in the tubule are patterned. Finally, I explore how the organ is positioned within the body cavity and consider the relationship between organ position and function.
The role of osmoregulation in the pathophysiology and management of Severe Ovarian Hyperstimulation Syndrome
Published in Human Fertility, 2013
Severe Ovarian Hyperstimulation Syndrome (OHSS), with an incidence of 1–2% of superovulation cycles, remains one of the most important complications of gonadotrophin use in assisted reproductive technologies because of its associated morbidity and rarely, mortality. Despite the wealth of scientific and clinical interest that this iatrogenic complication has generated, its pathophysiology is still not adequately elucidated and its management has thus remained empirical. Disorders of salt and water balance are two very important features that have been reported during severe OHSS. Some of the clinical and biochemical changes resulting from this disorder of salt and water balance are similar to those previously reported in pregnancy and liver cirrhosis. The pathophysiology of these clinical changes has been explained in part in pregnancy and liver cirrhosis by changes in osmoregulation function. It is this similarity in the clinical and biochemical changes in OHSS, pregnancy and liver cirrhosis that has prompted the investigation of the role of osmoregulation function in the pathophysiology of OHSS. The current article has been written to provide further details in support of recent excellent articles and guidelines, highlighting the physiological basis and rationale governing some aspects of, and the role of osmoregulation in the management of the OHSS syndrome.
Taurine and GABA neurotransmitter receptors, a relationship with therapeutic potential?
Published in Expert Review of Neurotherapeutics, 2019
Lenin Ochoa-de la Paz, Edgar Zenteno, Rosario Gulias-Cañizo, Hugo Quiroz-Mercado
Taurine is a β-amino acid present in high concentrations in different areas of the mammalian central nervous system (CNS). It participates in different physiological processes such as osmoregulation, signal transduction, antioxidant activity, trophic factor activity, modulation of calcium movements and neurotransmission. It is known that taurine is an agonist of GABAA receptors, and their affinity depends of the subunits that conform this receptor. GABA is the main inhibitory neurotransmitter of the CNS and exerts its effect through the activation of two types of specific receptors, called GABAA and GABAB. In the last years, changes in the expression pattern of the GABAA receptors subunits has been related to pathologies, such as epilepsy, depression and alcoholism, among others. This changes in the GABAA receptors conformation might be responsible of the loss in the effectiveness of the different drugs used in clinic protocols. Therefore, considering the physiological properties of taurine and the capacity to interact with GABAA receptors conformed by different subunits combinations, it is clear their great potential for the design of new pharmacological strategies aimed to treat the pathologies where GABA has shown a relevant participation.
Related Knowledge Centers
- Body Water
- Sodium
- Metabolism
- Homeostasis
- Electrolytes
- Body Fluid Compartments
- Intracellular Space