Phosphatidylethanolamine ( PE ) is a class of phospholipids found in biological membranes . They are synthesized by the addition of cytidine diphosphate - ethanolamine to diglycerides , releasing cytidine monophosphate . S -Adenosyl methionine can subsequently methylate the amine of phosphatidylethanolamines to yield phosphatidylcholines .
41-452: Phosphatidylethanolamines are found in all living cells, composing 25% of all phospholipids. In human physiology, they are found particularly in nervous tissue such as the white matter of brain , nerves, neural tissue, and in spinal cord , where they make up 45% of all phospholipids. Phosphatidylethanolamines play a role in membrane fusion and in disassembly of the contractile ring during cytokinesis in cell division . Additionally, it
82-559: A microscope slide because of the type of stain used. Cerebral and spinal white matter do not contain dendrites , neural cell bodies , or shorter axons, which can only be found in grey matter. White matter forms the bulk of the deep parts of the brain and the superficial parts of the spinal cord . Aggregates of grey matter such as the basal ganglia ( caudate nucleus , putamen , globus pallidus , substantia nigra , subthalamic nucleus , nucleus accumbens ) and brainstem nuclei ( red nucleus , cranial nerve nuclei) are spread within
123-434: A cerebral hemisphere is 2% of the total number of cortico-cortical fibers (across cortical areas) and is roughly the same number as those that communicate between the two hemispheres in the brain's largest white tissue structure, the corpus callosum . Schüz and Braitenberg note "As a rough rule, the number of fibres of a certain range of lengths is inversely proportional to their length." The proportion of blood vessels in
164-442: A factor in the severity of obstructive sleep apnea . The study of white matter has been advanced with the neuroimaging technique called diffusion tensor imaging where magnetic resonance imaging (MRI) brain scanners are used. As of 2007, more than 700 publications have been published on the subject. A 2009 paper by Jan Scholz and colleagues used diffusion tensor imaging (DTI) to demonstrate changes in white matter volume as
205-400: A man at 80 years of age has 97,200 km and a woman 82,000 km. Most of this reduction is due to the loss of thinner fibers. However, this reduction may correlate with men having larger brains than women and with brain size reducing with age. White matter is the tissue through which messages pass between different areas of grey matter within the central nervous system. The white matter
246-407: A result of learning a new motor task (e.g. juggling). The study is important as the first paper to correlate motor learning with white matter changes. Previously, many researchers had considered this type of learning to be exclusively mediated by dendrites, which are not present in white matter. The authors suggest that electrical activity in axons may regulate myelination in axons. Or, gross changes in
287-428: A wide variety of foods such as chocolate , soybean milk , infant formula , and other processed foods . The levels of Amadori-phosphatidylethanolamine products are higher in foods with high lipid and sugar concentrations that have high temperatures in processing. Additional studies have found that Amadori-phosphatidylethanolamine may play a role in vascular disease , act as the mechanism by which diabetes can increase
328-472: Is -20 °C. If the lipids had two palmitoyl chains, phosphatidylethanolamine would melt at 63 °C while phosphatidylcholine would melt already at 41 °C. Lower melting temperatures correspond, in a simplistic view, to more fluid membranes. In humans, metabolism of phosphatidylethanolamine is thought to be important in the heart. When blood flow to the heart is restricted, the asymmetrical distribution of phosphatidylethanolamine between membrane leaflets
369-410: Is a key pathway for viruses to enter cells via apoptotic mimicry . Its exposure on the outer surface of a membrane marks the cell for destruction via apoptosis . Phosphatidylserine is a phospholipid —more specifically a glycerophospholipid —which consists of two fatty acids attached in ester linkage to the first and second carbon of glycerol and serine attached through a phosphodiester linkage to
410-446: Is also made via the cytidine diphosphate-ethanolamine pathway, using ethanolamine as the substrate. Through several steps taking place in both the cytosol and endoplasmic reticulum , the synthesis pathway yields the end product of phosphatidylethanolamine. Phosphatidylethanolamine is also found abundantly in soy or egg lecithin and is produced commercially using chromatographic separation. Synthesis of phosphatidylethanolamine through
451-479: Is continuous throughout one's lifetime due to neuroplasticity , and is a contributing factor rather than determinant factor of certain functional deficits due to compensating effects in other brain regions. The integrity of white matter declines due to aging. Nonetheless, regular aerobic exercise appears to either postpone the aging effect or in turn enhance the white matter integrity in the long run. Changes in white matter volume due to inflammation or injury may be
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#1732876320174492-583: Is currently unknown but may play a role in the regulation of the rate of synthesis in this pathway. Phosphatidylethanolamines in food break down to form phosphatidylethanolamine-linked Amadori products as a part of the Maillard reaction . These products accelerate membrane lipid peroxidation , causing oxidative stress to cells that come in contact with them. Oxidative stress is known to cause food deterioration and several diseases. Significant levels of Amadori-phosphatidylethanolamine products have been found in
533-547: Is disrupted, and as a result the membrane is disrupted. Additionally, phosphatidylethanolamine plays a role in the secretion of lipoproteins in the liver. This is because vesicles for secretion of very low-density lipoproteins coming off of the Golgi apparatus have a significantly higher phosphatidylethanolamine concentration when compared to other vesicles containing very low-density lipoproteins. Phosphatidylethanolamine has also shown to be able to propagate infectious prions without
574-461: Is due to its usual preservation in formaldehyde . White matter is composed of bundles, which connect various grey matter areas (the locations of nerve cell bodies) of the brain to each other, and carry nerve impulses between neurons. Myelin acts as an insulator, which allows electrical signals to jump , rather than coursing through the axon, increasing the speed of transmission of all nerve signals. The total number of long range fibers within
615-685: Is found in soy lecithin at about 3% of total phospholipids. Table 1. Phosphatidylserine content in different foods. A panel of the European Food Safety Authority concluded that a cause and effect relationship cannot be established between the consumption of phosphatidylserine and "memory and cognitive functioning in the elderly", "mental health/cognitive function" and "stress reduction and enhanced memory function". This conclusion follows because bovine brain cortex- and soy-based phosphatidylserine are different substances and might, therefore, have different biological activities. Therefore,
656-670: Is likely effective for enhancing cognitive function in older people with mild cognitive impairment. Some studies have suggested that whether the phosphatidylserine is plant- or animal-derived may have significance, with the FDA's statement applying specifically to soy-derived products. Initially, phosphatidylserine supplements were derived from bovine cortex. However, due to the risk of potential transfer of infectious diseases such as bovine spongiform encephalopathy (or "mad cow disease"), soy-derived supplements became an alternative. A 2002 safety report determined supplementation in elderly people at
697-454: Is not present, the transport proteins have incorrect tertiary structures and do not function correctly. Phosphatidylethanolamine also enables bacterial multidrug transporters to function properly and allows the formation of intermediates that are needed for the transporters to properly open and close. As a lecithin , phosphatidylethanolamine consists of a combination of glycerol esterified with two fatty acids and phosphoric acid . Whereas
738-430: Is performed from the phosphatidylethanolamine by the successive action of two enzymes, N - acetyltransferase and phospholipase -D. Where phosphatidylcholine is the principal phospholipid in animals, phosphatidylethanolamine is the principal one in bacteria . One of the primary roles for phosphatidylethanolamine in bacterial membranes is to spread out the negative charge caused by anionic membrane phospholipids . In
779-448: Is the enzyme that is used to decarboxylate phosphatidylserine in the first pathway. The phosphatidylserine decarboxylation pathway is the main source of synthesis for phosphatidylethanolamine in the membranes of the mitochondria . Phosphatidylethanolamine produced in the mitochondrial membrane is also transported throughout the cell to other membranes for use. In a process that mirrors phosphatidylcholine synthesis, phosphatidylethanolamine
820-463: Is the most common of the inflammatory demyelinating diseases of the central nervous system which affect white matter. In MS lesions, the myelin sheath around the axons is deteriorated by inflammation . Alcohol use disorders are associated with a decrease in white matter volume. Amyloid plaques in white matter may be associated with Alzheimer's disease and other neurodegenerative diseases . Other changes that commonly occur with age include
861-454: Is thought that phosphatidylethanolamine regulates membrane curvature . Phosphatidylethanolamine is an important precursor, substrate , or donor in several biological pathways. As a polar head group, phosphatidylethanolamine creates a more viscous lipid membrane compared to phosphatidylcholine . For example, the melting temperature of di-oleoyl-phosphatidylethanolamine is -16 °C while the melting temperature of di-oleoyl-phosphatidylcholine
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#1732876320174902-433: Is white because of the fatty substance (myelin) that surrounds the nerve fibers (axons). This myelin is found in almost all long nerve fibers, and acts as an electrical insulation. This is important because it allows the messages to pass quickly from place to place. Unlike grey matter, which peaks in development in a person's twenties, the white matter continues to develop, and peaks in middle age. Multiple sclerosis (MS)
943-411: The phosphatidylserine decarboxylation pathway occurs rapidly in the inner mitochondrial membrane . However, phosphatidylserine is made in the endoplasmic reticulum . Because of this, the transport of phosphatidylserine from the endoplasmic reticulum to the mitochondrial membrane and then to the inner mitochondrial membrane limits the rate of synthesis via this pathway. The mechanism for this transport
984-469: The PS level in the plasma membrane of neurons has a significant impact on these signaling processes. Phosphatidylserine is formed in bacteria (such as E. coli ) through a displacement of cytidine monophosphate (CMP) through a nucleophilic attack by the hydroxyl functional group of serine. CMP is formed from CDP-diacylglycerol by PS synthase. Phosphatidylserine can eventually become phosphatidylethanolamine by
1025-420: The assistance of any proteins or nucleic acids , which is a unique characteristic of it. Phosphatidylethanolamine is also thought to play a role in blood clotting, as it works with phosphatidylserine to increase the rate of thrombin formation by promoting binding to factor V and factor X , two proteins which catalyze the formation of thrombin from prothrombin . The synthesis of endocannabinoid anandamide
1066-461: The bacterium E. coli , phosphatidylethanolamine play a role in supporting lactose permeases active transport of lactose into the cell, and may play a role in other transport systems as well. Phosphatidylethanolamine plays a role in the assembly of lactose permease and other membrane proteins. It acts as a 'chaperone' to help the membrane proteins correctly fold their tertiary structures so that they can function properly. When phosphatidylethanolamine
1107-436: The cerebral white matter. One small study found that men have more white matter than women both in volume and in length of myelinated axons, and that volume and length reduced with age. (This study only included 36 participants. ) At the age of 20, the total length of myelinated fibers in men is 176,000 km while that of a woman is 149,000 km. There is a decline in total length with age of about 10% each decade such that
1148-512: The cerebral white matter. The cerebellum is structured in a similar manner as the cerebrum, with a superficial mantle of cerebellar cortex, deep cerebellar white matter (called the " arbor vitae ") and aggregates of grey matter surrounded by deep cerebellar white matter ( dentate nucleus , globose nucleus , emboliform nucleus , and fastigial nucleus ). The fluid-filled cerebral ventricles (lateral ventricles, third ventricle , cerebral aqueduct , fourth ventricle ) are also located deep within
1189-955: The development of leukoaraiosis , which is a rarefaction of the white matter that can be correlated with a variety of conditions, including loss of myelin pallor, axonal loss, and diminished restrictive function of the blood–brain barrier . There is also evidence that substance abuse may damage white matter microstructure, though prolonged abstinence may in certain cases reverse such white matter changes. White matter lesions on magnetic resonance imaging are linked to several adverse outcomes, such as cognitive impairment and depression . White matter hyperintensities are often found in patients with vascular dementia , particularly with small vessel/subcortical subtypes of vascular dementia. Smaller volumes (in terms of group averages) of white matter might be associated with larger deficits in attention , declarative memory , executive functions , intelligence , and academic achievement . However, volume change
1230-457: The diameter or packing density of the axon might cause the change. A more recent DTI study by Sampaio-Baptista and colleagues reported changes in white matter with motor learning along with increases in myelination. Phosphatidylserine Phosphatidylserine (abbreviated Ptd-L-Ser or PS ) is a phospholipid and is a component of the cell membrane . It plays a key role in cell cycle signaling, specifically in relation to apoptosis . It
1271-434: The distribution of action potentials , acting as a relay and coordinating communication between different brain regions. White matter is named for its relatively light appearance resulting from the lipid content of myelin . However, the tissue of the freshly cut brain appears pinkish-white to the naked eye because myelin is composed largely of lipid tissue veined with capillaries . Its white color in prepared specimens
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1312-638: The enzyme PS decarboxylase (forming carbon dioxide as a byproduct). Similar to bacteria, yeast can form phosphatidylserine in an identical pathway. In mammals, phosphatidylserine is instead derived from phosphatidylethanolamine or phosphatidylcholine through one of two Ca -dependent head-group exchange reactions in the endoplasmic reticulum. Both reactions require a serine but produce an ethanolamine or choline , respectively. These are promoted by phosphatidylserine synthase 1 (PSS1) or 2 (PSS2). Conversely, phosphatidylserine can also give rise to phosphatidylethanolamine and phosphatidylcholine , although in animals
1353-556: The incidence of cancer , and potentially play a role in other diseases as well. Amadori-phosphatidylethanolamine has a higher plasma concentration in diabetes patients than healthy people, indicating it may play a role in the development of the disease or be a product of the disease. White matter White matter refers to areas of the central nervous system (CNS) that are mainly made up of myelinated axons , also called tracts . Long thought to be passive tissue, white matter affects learning and brain functions, modulating
1394-408: The inner to the outer leaflet of the cell membrane, serving as a signal for phagocytic cells to engulf the dying cell. The average daily phosphatidylserine intake in a Western diet is estimated to be 130 mg. Phosphatidylserine may be found in meat and fish. Only small amounts are found in dairy products and vegetables, with the exception of white beans and soy lecithin . Phosphatidylserine
1435-474: The pathway to generate phosphatidylcholine from phosphatidylserine only operates in the liver. PS has been studied for its potential in improving memory, learning, and concentration. Supplementation with PS has been shown to have little effect in enhancing cognitive performance in the elderly and individuals with cognitive decline. Phosphatidylserine plays a crucial role in the process of apoptosis, or programmed cell death. During apoptosis, PS translocates from
1476-447: The phosphate group is combined with choline in phosphatidylcholine, it is combined with ethanolamine in phosphatidylethanolamine. The two fatty acids may be identical or different, and are usually found in positions 1,2 (less commonly in positions 1,3). The phosphatidylserine decarboxylation pathway and the cytidine diphosphate-ethanolamine pathways are used to synthesize phosphatidylethanolamine. Phosphatidylserine decarboxylase
1517-450: The phospholipids in the human cerebral cortex. In the plasma membrane, PS is localized exclusively in the cytoplasmic leaflet where it forms part of protein docking sites necessary for the activation of several key signaling pathways. These include the Akt, protein kinase C (PKC) and Raf-1 signaling that is known to stimulate neuronal survival, neurite growth, and synaptogenesis. Modulation of
1558-508: The results of studies using phosphatidylserine from different sources cannot be generalized. In May, 2003 the Food and Drug Administration gave "qualified health claim" status to phosphatidylserine thus allowing labels to state "consumption of phosphatidylserine may reduce the risk of dementia and cognitive dysfunction in the elderly" along with the disclaimer "very limited and preliminary scientific research suggests that phosphatidylserine may reduce
1599-408: The risk of cognitive dysfunction in the elderly." According to the FDA, there is a lack of scientific agreement amongst qualified experts that a relationship exists between phosphatidylserine and cognitive function. More recent reviews have suggested that the relationship may be more robust, though the mechanism remains unclear. A 2020 review of three clinical trials found that phosphatidylserine
1640-438: The third carbon of the glycerol. Phosphatidylserine sourced from plants differs in fatty acid composition from that sourced from animals. It is commonly found in the inner (cytoplasmic) leaflet of biological membranes. It is almost entirely found in the inner monolayer of the membrane with only less than 10% of it in the outer monolayer. Phosphatidylserine (PS) is the major acidic phospholipid class that accounts for 13–15% of
1681-432: The white matter in nonelderly adults is 1.7–3.6%. The other main component of the brain is grey matter (actually pinkish tan due to blood capillaries), which is composed of neurons . The substantia nigra is a third colored component found in the brain that appears darker due to higher levels of melanin in dopaminergic neurons than its nearby areas. Note that white matter can sometimes appear darker than grey matter on