The effect of methyl lidocaine on lysophospholipid metabolism in hamster heart

1990 ◽  
Vol 68 (4) ◽  
pp. 745-750 ◽  
Author(s):  
Paul G. Tardi ◽  
Ricky Y. K. Man ◽  
Christopher R. McMaster ◽  
Patrick C. Choy
Keyword(s):  
Physiological Role ◽  
Fatty Acyl ◽  
The Other ◽  
Acylation Reaction ◽  
Alternate Pathway ◽  
Mammalian Tissues ◽  
High Concern ◽  
Acyl Chains ◽  
Hamster Heart

An important feature in the remodelling of fatty acyl chains in cellular phospholipids is the acylation of lysophospholipids. Since lysophospholipids are cytolytic al high concern rat ions, the acylation reaction may provide an alternate pathway for the removal of cellular lysophospholipids. However, the physiological role of the acylation process in the maintenance of lysophospholipid levels in mammalian tissues has not been clearly defined. In this study, methyl lidocaine was found to inhibit both lysophosphatidylcholine:acyl-CoA and lysophosphatidylethanolamine:acyl-CoA acyltransferase activities in the hamster heart, but the drug had no effect on the other lysophospholipid metabolic enzymes. When the heart was perfused with 0.5 mg methyl lidocaine/mL, acyltransferase activities were attenuated, but there was no change in the activities of phospholipase A or lysophospholipase. The levels of the major lysophospholipids in the heart were not altered by methyl lidocaine perfusion. When the hearts were perfused with labelled lysophospholipid in the presence of methyl lidocaine, there was a reduction in the formation of the phospholipid and an increase in the release of the free fatty acid. However, the labelling of lysophospholipid in the heart was not altered by methyl lidocaine. We postulate that the acylation reaction has no direct contribution to the maintenance of the lysophospholipid levels in the heart.Key words: lysophosphatidylcholine, lysophosphatidylethanolamine, acyltransferase, methyl lidocaine, hamster heart.

How do mechanosensitive channels sense membrane tension?

2016 ◽  
Vol 44 (4) ◽  
pp. 1019-1025 ◽  
Author(s):  
Tim Rasmussen
Keyword(s):  
Membrane Lipids ◽  
Osmotic Shock ◽  
Md Simulations ◽  
Fatty Acyl ◽  
Membrane Bilayer ◽  
Cross Sectional ◽  
Conducting Path ◽  
Lipid Chain ◽  
Acyl Chains

Mechanosensitive (MS) channels provide protection against hypo-osmotic shock in bacteria whereas eukaryotic MS channels fulfil a multitude of important functions beside osmoregulation. Interactions with the membrane lipids are responsible for the sensing of mechanical force for most known MS channels. It emerged recently that not only prokaryotic, but also eukaryotic, MS channels are able to directly sense the tension in the membrane bilayer without any additional cofactor. If the membrane is solely viewed as a continuous medium with specific anisotropic physical properties, the sensitivity towards tension changes can be explained as result of the hydrophobic coupling between membrane and transmembrane (TM) regions of the channel. The increased cross-sectional area of the MS channel in the active conformation and elastic deformations of the membrane close to the channel have been described as important factors. However, recent studies suggest that molecular interactions of lipids with the channels could play an important role in mechanosensation. Pockets in between TM helices were identified in the MS channel of small conductance (MscS) and YnaI that are filled with lipids. Less lipids are present in the open state of MscS than the closed according to MD simulations. Thus it was suggested that exclusion of lipid fatty acyl chains from these pockets, as a consequence of increased tension, would trigger gating. Similarly, in the eukaryotic MS channel TRAAK it was found that a lipid chain blocks the conducting path in the closed state. The role of these specific lipid interactions in mechanosensation are highlighted in this review.

scholarly journals Effect of 1,5-Anhydro-D-Fructose on the Inhibition of Adipogenesis in 3T3-L1 Adipocytes

2012 ◽  
Vol 7 (11) ◽  
pp. 1934578X1200701 ◽  
Author(s):  
Akiko Kojima-Yuasa ◽  
Yohei Deguchi ◽  
Yotaro Konishi ◽  
Isao Matsui-Yuasa
Keyword(s):  
Metabolic Diseases ◽  
Physiological Role ◽  
Structural Similarity ◽  
Regulation Of Transcription ◽  
Energy Sensor ◽  
Mammalian Tissues ◽  
Cellular Lipid Accumulation ◽  
Amp Activated Protein Kinase

1,5-Anhydro-D-fructose (1,5-AF) is a monosaccharide that shares a structural similarity to glucose. 1,5-AF is found in fungi, algae, Escherichia coli and rat liver and is produced by the degradation of starch and glycogen, which is catalyzed by the enzyme α-1,4-glucan lyase. However, the physiological role of 1,5-AF in mammalian tissues is not well understood. Here, we investigated the anti-obesity potential of 1,5-AF on adipogenesis in 3T3-L1 adipocytes. 1,5-AF caused a significant decrease in GPDH activity in 3T3-L1 preadipocytes and mature adipocytes without eliciting cytotoxicity, and inhibited cellular lipid accumulation through down-regulation of transcription factors such as PPARγ and C/EBPα. 1,5-AF also induced dose-dependent phosphorylation of AMP-activated protein kinase (AMPK), a cellular energy sensor. However, the total AMPK protein content remained unchanged. Furthermore, 1,5-AF increased the levels of reactive oxygen species, an important upstream signal for AMPK activation in 3T3-L1 adipocytes. Our results show that 1,5-AF exerts anti-obesity action in vitro and suggest that 1,5-AF is potentially a novel preventative agent for obesity and other metabolic diseases.

scholarly journals LOW RESISTANCE CONNECTIONS BETWEEN CELLS IN THE DEVELOPING ANTHER OF THE LILY

1970 ◽  
Vol 45 (3) ◽  
pp. 565-575 ◽  
Author(s):  
Nicholas C. Spitzer
Keyword(s):  
Electrical Coupling ◽  
Physiological Role ◽  
Lilium Longiflorum ◽  
The Other ◽  
Animal Tissues ◽  
Low Resistance ◽  
First Case ◽  
Cytoplasmic Bridges ◽  
Germinal Cells

Low resistance junctions were demonstrated between cells in anthers from young buds of Lilium longiflorum Croft by standard electrophysiological techniques. Electrodes containing a dye were used to stain impaled cells for later histological identification. Electrical coupling is widespread; germinal cells are coupled to one another; coupling is also observed between somatic elements, and germinal and somatic cells are similarly interconnected. Cytoplasmic bridges are implicated in the first case; plasmodesmata are probably responsible for the interactions in the other two. Although the physiological role of the low resistance junctions shown here and present in embryonic animal tissues is unknown, the possible function of this form of intercellular communication in the development of the anther is discussed.

scholarly journals Widespread Head-to-Head Hydrocarbon Biosynthesis in Bacteria and Role of OleA

2010 ◽  
Vol 76 (12) ◽  
pp. 3850-3862 ◽  
Author(s):  
David J. Sukovich ◽  
Jennifer L. Seffernick ◽  
Jack E. Richman ◽  
Jeffrey A. Gralnick ◽  
Lawrence P. Wackett
Keyword(s):  
Xanthomonas Campestris ◽  
Gene Deletion ◽  
Shewanella Oneidensis ◽  
Fatty Acyl ◽  
Double Bonds ◽  
Acyl Chains ◽  
Hydrocarbon Biosynthesis ◽  
Structural Alignments ◽  
Long Chain

ABSTRACT Previous studies identified the oleABCD genes involved in head-to-head olefinic hydrocarbon biosynthesis. The present study more fully defined the OleABCD protein families within the thiolase, α/β-hydrolase, AMP-dependent ligase/synthase, and short-chain dehydrogenase superfamilies, respectively. Only 0.1 to 1% of each superfamily represents likely Ole proteins. Sequence analysis based on structural alignments and gene context was used to identify highly likely ole genes. Selected microorganisms from the phyla Verucomicrobia, Planctomyces, Chloroflexi, Proteobacteria, and Actinobacteria were tested experimentally and shown to produce long-chain olefinic hydrocarbons. However, different species from the same genera sometimes lack the ole genes and fail to produce olefinic hydrocarbons. Overall, only 1.9% of 3,558 genomes analyzed showed clear evidence for containing ole genes. The type of olefins produced by different bacteria differed greatly with respect to the number of carbon-carbon double bonds. The greatest number of organisms surveyed biosynthesized a single long-chain olefin, 3,6,9,12,15,19,22,25,28-hentriacontanonaene, that contains nine double bonds. Xanthomonas campestris produced the greatest number of distinct olefin products, 15 compounds ranging in length from C28 to C31 and containing one to three double bonds. The type of long-chain product formed was shown to be dependent on the oleA gene in experiments with Shewanella oneidensis MR-1 ole gene deletion mutants containing native or heterologous oleA genes expressed in trans. A strain deleted in oleABCD and containing oleA in trans produced only ketones. Based on these observations, it was proposed that OleA catalyzes a nondecarboxylative thiolytic condensation of fatty acyl chains to generate a β-ketoacyl intermediate that can decarboxylate spontaneously to generate ketones.

scholarly journals Accessory proteins of the zDHHC family of S-acylation enzymes

2020 ◽  
Vol 133 (22) ◽  
pp. jcs251819
Author(s):  
Christine Salaun ◽  
Carolina Locatelli ◽  
Filip Zmuda ◽  
Juan Cabrera González ◽  
Luke H. Chamberlain
Keyword(s):  
Fatty Acyl ◽  
Accessory Proteins ◽  
Enzyme Substrate ◽  
Essential Components ◽  
Selenoprotein K ◽  
Acyl Chains ◽  
The Stability ◽  
And Function ◽  
Encoding Genes

ABSTRACTAlmost two decades have passed since seminal work in Saccharomyces cerevisiae identified zinc finger DHHC domain-containing (zDHHC) enzymes as S-acyltransferases. These enzymes are ubiquitous in the eukarya domain, with 23 distinct zDHHC-encoding genes in the human genome. zDHHC enzymes mediate the bulk of S-acylation (also known as palmitoylation) reactions in cells, transferring acyl chains to cysteine thiolates, and in so-doing affecting the stability, localisation and function of several thousand proteins. Studies using purified components have shown that the minimal requirements for S-acylation are an appropriate zDHHC enzyme–substrate pair and fatty acyl-CoA. However, additional proteins including GCP16 (also known as Golga7), Golga7b, huntingtin and selenoprotein K, have been suggested to regulate the activity, stability and trafficking of certain zDHHC enzymes. In this Review, we discuss the role of these accessory proteins as essential components of the cellular S-acylation system.

A possible physiological role of milk epidermal growth factor in neonatal eyelid opening

1987 ◽  
Vol 252 (2) ◽  
pp. R376-R379
Author(s):  
O. Tsutsumi ◽  
A. Tsutsumi ◽  
T. Oka
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Neonatal Period ◽  
Physiological Role ◽  
The Other ◽  
Simultaneous Administration ◽  
Newborn Mice ◽  
Submandibular Glands ◽  
Epidermal Growth

The eyelid opening of newborn mice occurs normally on day 13.9 +/- 1.8 after birth. When newborn mice were injected with anti-epidermal growth factor (EGF) antibody every other day starting on day 1 after birth, the eyelid opening was delayed by approximately 3 days. The effect of anti-EGF became less prominent as the treatment was started at later times: when it was given from day 7, no delay in eyelid opening was observed. On the other hand, eyelid opening was enhanced by approximately 3 days by EGF injection given on day 3 for every other day. This effect of EGF was antagonized by simultaneous administration of the anti-EGF antibody. EGF was present at a concentration of 6.6 ng/ml in the plasma of 1-wk-old pups nursed by their mother, but it was not detectable (less than 0.1 ng/ml) in the plasma of 3-wk-old weaned pups. EGF concentration in the submandibular glands, however, was 17 times greater in 3- than in 1-wk-old pups, i.e., 4.66 and 0.28 ng/mg of wet tissue, respectively. These results suggest that milk EGF may play a physiological role in eyelid opening during the neonatal period.

scholarly journals noeM, a New Nodulation Gene Involved in the Biosynthesis of Nod Factors with an Open-Chain Oxidized Terminal Residue and in the Symbiosis with Mimosa pudica

2019 ◽  
Vol 32 (12) ◽  
pp. 1635-1648 ◽  
Author(s):  
Benoit Daubech ◽  
Verena Poinsot ◽  
Agnieszka Klonowska ◽  
Delphine Capela ◽  
Clémence Chaintreuil ◽  
...  
Keyword(s):  
Transmembrane Protein ◽  
Fatty Acyl ◽  
Mimosa Pudica ◽  
Nod Factors ◽  
Open Chain ◽  
Nod Factor ◽  
Terminal Residue ◽  
Fatty Acid Hydroxylase ◽  
Acyl Chains

The β-rhizobium Cupriavidus taiwanensis is a nitrogen-fixing symbiont of Mimosa pudica. Nod factors produced by this species were previously found to be pentameric chitin-oligomers carrying common C18:1 or C16:0 fatty acyl chains, N-methylated and C-6 carbamoylated on the nonreducing terminal N-acetylglucosamine and sulfated on the reducing terminal residue. Here, we report that, in addition, C. taiwanensis LMG19424 produces molecules where the reducing sugar is open and oxidized. We identified a novel nodulation gene located on the symbiotic plasmid pRalta, called noeM, which is involved in this atypical Nod factor structure. noeM encodes a transmembrane protein bearing a fatty acid hydroxylase domain. This gene is expressed during symbiosis with M. pudica and requires NodD and luteolin for optimal expression. The closest noeM homologs formed a separate phylogenetic clade containing rhizobial genes only, which are located on symbiosis plasmids downstream from a nod box. Corresponding proteins, referred to as NoeM, may have specialized in symbiosis via the connection to the nodulation pathway and the spread in rhizobia. noeM was mostly found in isolates of the Mimoseae tribe, and specifically detected in all tested strains able to nodulate M. pudica. A noeM deletion mutant of C. taiwanensis was affected for the nodulation of M. pudica, confirming the role of noeM in the symbiosis with this legume.

scholarly journals β-Fructofuranosidases from roots of dandelion (Taraxacum officinale Weber)

1972 ◽  
Vol 126 (3) ◽  
pp. 569-573 ◽  
Author(s):  
P. P. Rutherford ◽  
A. C. Deacon
Keyword(s):  
General Formula ◽  
Soluble Protein ◽  
Hydrolytic Enzymes ◽  
Deae Cellulose ◽  
Physiological Role ◽  
Taraxacum Officinale ◽  
The Other ◽  
Ph Optimum ◽  
Cellulose Column

1. Three β-fructofuranosidases were separated by chromatography on a DEAE-cellulose column from the soluble protein extracted from dandelion (Taraxacum officinale Weber) roots. 2. One enzyme, which acted on sucrose, was characterized as an invertase, with a Km of 2.00×10-2M and pH optimum of 7.5. 3. The other two enzymes are hydrolases (A and B), which act on the inulin series of oligosaccharides [general formula glucose-fructose-(fructose)n]. They both have a pH optimum of 4.0 and Km of 1.54×10-2M but differ in their chromatographic behaviour on DEAE-cellulose. Neither of the hydrolases is inhibited by sucrose. 4. The physiological role of these three hydrolytic enzymes is discussed.

scholarly journals The multifarious roles of Tol-Pal in Gram-negative bacteria

2020 ◽  
Vol 44 (4) ◽  
pp. 490-506
Author(s):  
Joanna Szczepaniak ◽  
Cara Press ◽  
Colin Kleanthous
Keyword(s):  
Outer Membrane ◽  
Cell Envelope ◽  
Physiological Role ◽  
Proton Motive Force ◽  
The Other ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
The 1960S ◽  
Shed Light

ABSTRACT In the 1960s several groups reported the isolation and preliminary genetic mapping of Escherichia coli strains tolerant towards the action of colicins. These pioneering studies kick-started two new fields in bacteriology; one centred on how bacteriocins like colicins exploit the Tol (or more commonly Tol-Pal) system to kill bacteria, the other on the physiological role of this cell envelope-spanning assembly. The following half century has seen significant advances in the first of these fields whereas the second has remained elusive, until recently. Here, we review work that begins to shed light on Tol-Pal function in Gram-negative bacteria. What emerges from these studies is that Tol-Pal is an energised system with fundamental, interlinked roles in cell division – coordinating the re-structuring of peptidoglycan at division sites and stabilising the connection between the outer membrane and underlying cell wall. This latter role is achieved by Tol-Pal exploiting the proton motive force to catalyse the accumulation of the outer membrane peptidoglycan associated lipoprotein Pal at division sites while simultaneously mobilising Pal molecules from around the cell. These studies begin to explain the diverse phenotypic outcomes of tol-pal mutations, point to other cell envelope roles Tol-Pal may have and raise many new questions.

scholarly journals Role of lipid reactions in quality of oat products

2008 ◽  
Vol 13 (1-2) ◽  
pp. 88 ◽  
Author(s):  
P. LEHTINEN ◽  
S. LAAKSO
Keyword(s):  
Fatty Acyl ◽  
Enzymatic Oxidation ◽  
Food Markets ◽  
Huge Impact ◽  
Acyl Chains ◽  
Underlying Mechanisms ◽  
Hydrolysis Of ◽  
Global Food

In traditional oat processing practice the control of lipid reactions relies largely on empirical experiences and dogmatic principles rather than on profound understanding of the underlying mechanisms. However, in today’s global food markets, the industry faces strict challenges in the development of new processes and applications where the prior experience is unsatisfactory or insufficient. The storage stability of novel oat products can be greatly enhanced by taking the mechanisms of lipid deterioration into account, and by adjusting the processing conditions accordingly so that these reactions can be minimized. The lipid reactions in oat products result in two different unwanted properties: bitter, astringent, taste or a rancid flavor. Chemically, these properties are associated to enzymatic hydrolysis of ester bonds and non-enzymatic oxidation of unsaturated fatty acyl chains respectively. The processing history oat product has a huge impact on which of these reactions predominates in oat products. The review focuses on the reactions of lipids in processed oat products, and identifies factors that are critical for enhanced shelf-life.;

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