Sexual reproduction is marked by the fusion of the sperm cell with the oocyte during fertilization to produce the diploid zygote, in which the lipids in the sperm plasma membrane play an important role. Due to the loss of most cell organelles and DNA transcription, spermatozoa lack protein expression and vesicular transport. However, the lipids of the sperm plasma membrane undergo complicated dynamic changes, which may facilitate the capacitation, binding with zona pellucida, acrosome reaction and fusion of the sperm cell with the oocyte. This paper summarizes the progress in the studies of the lipids in the sperm plasma membrane, their composition, structure, peroxidation, metabolism and role in fertilization.
Acrosome Reaction ; Animals ; Cell Membrane ; chemistry ; Fertilization ; Humans ; Male ; Membrane Lipids ; metabolism ; Sperm Capacitation ; Spermatozoa ; chemistry

A specialized tissue type, the keratinizing epithelium, protects terrestrial mammals from water loss and noxious physical, chemical and mechanical insults. This barrier between the body and the environment is constantly maintained by reproduction of inner living epidermal keratinocytes which undergo a process of terminal differentiation and then migrate to the surface as interlocking layers of dead stratum corneum cells. These cells provide the bulwark of mechanical and chemical protection, and together with their intercellular lipid surroundings, confer water-impermeability. Much of this barrier function is provided by the cornified cell envelope (CE), an extremely tough protein/lipid polymer structure formed just below the cytoplasmic membrane and subsequently resides on the exterior of the dead cornified cells. It consists of two parts: a protein envelope and a lipid envelope. The protein envelope is thought to contribute to the biomechanical properties of the CE as a result of cross-linking of specialized CE structural proteins by both disulfide bonds and N(epsilon)-(gamma-glutamyl)lysine isopeptide bonds formed by transglutaminases. Some of the structural proteins involved include involucrin, loricrin, small proline rich proteins, keratin intermediate filaments, elafin, cystatin A, and desmosomal proteins. The lipid envelope is located on the exterior of and covalently attached by ester bonds to the protein envelope and consists of a monomolecular layer of omega-hydroxyceramides. These not only serve of provide a Teflon-like coating to the cell, but also interdigitate with the intercellular lipid lamellae perhaps in a Velcro-like fashion. In fact the CE is a common feature of all stratified squamous epithelia, although its precise composition, structure and barrier function requirements vary widely between epithelia. Recent work has shown that a number of diseases which display defective epidermal barrier function, generically known as ichthyoses, are the result of genetic defects of the synthesis of either CE proteins, the transglutaminase 1 cross-linking enzyme, or defective metabolism of skin lipids.
Animal ; Cell Membrane/metabolism ; Epidermis/metabolism* ; Epidermis/chemistry* ; Human ; Ichthyosis/metabolism ; Ichthyosis/genetics ; Keratinocytes/metabolism* ; Keratinocytes/chemistry ; Membrane Lipids/metabolism* ; Membrane Proteins/metabolism* ; Protein-Glutamine gamma-Glutamyltransferase/metabolism

Mycoplamas are a group of wall-less prokaryotes widely distributed in nature, some of which are pathogenic for humans and animals. There are many lipoproteins anchored on the outer face of the plasma membrane, called lipid-associated membrane proteins (LAMPs). LAMPs are highly antigenic and could undergo phase and size variation, and are recognized by the innate immune system through Toll-like receptors (TLR) 2 and 6. LAMPs can modulate the immune system, and could induce immune cells apoptosis or death. In addition, they may associate with malignant transformation of host cells and are also considered to be cofactors in the progression of AIDS.
Animals ; Humans ; Lipids ; Membrane Proteins ; metabolism ; Mycoplasma ; physiology ; Mycoplasma Infections ; immunology ; metabolism ; microbiology ; pathology ; Protein Binding ; Signal Transduction

Free fatty acid profiles of wild type and fatty acyl-ACP synthase deletion mutant strain of Synechocystis sp. PCC6803 indicated that one origin of these fatty acids is the process of lipid remodeling or lipid degradation. Lipase is the key enzyme involved in this process. The gene sll1969 is the sole gene encodes a putative lipase in Synechocystis sp. PCC6803. To identify the function of this gene and its role in fatty acid metabolism, we cloned the sll1969 from genomic DNA, overexpressed it in Escherichia coli BL21 (DE3) using pET expression system and purified this recombinant enzyme with Nickel-nitrilotriacetic acid affinity chromatography. The enzyme activity was assayed by spectrophotometric with p-nitro-phenylbutyrate as substrate. The K(m) and k(cat) of the enzyme is (1.16 +/- 0.01) mmol/L and (332.8 +/- 10.0)/min, respectively toward p-nitro-phenylbutyrate at 30 degrees C. The optimal temperature of the enzyme is 55 degrees C. To investigate the biological role of Sll1969 in fatty acid metabolism in cyanobacteria, we constructed sll1969 deletion and overexpression mutant strains in the background of fatty acyl-ACP synthase deletion mutant of Synechocystis sp. PCC6803. The analyses of the content of free fatty acids in different mutant strains showed that the contents of Sll1969 and free fatty acid are positively correlated. The free fatty acid profiles of the sll1969 mutant strains suggested this enzyme is not the sole enzyme for degrading lipid in Synechocystis sp. PCC6803.
Escherichia coli ; genetics ; metabolism ; Fatty Acids, Nonesterified ; metabolism ; Lipase ; biosynthesis ; genetics ; Membrane Lipids ; genetics ; metabolism ; Mutation ; Recombinant Proteins ; biosynthesis ; genetics ; metabolism ; Synechocystis ; enzymology ; genetics ; metabolism

The fusion between liposome-liposome, liposome-biomembarnes induced by acid-sensitive polymers has been systematically investigated. The polymer-liposomes were constructed by post-insertion method with the poly (2-ethylacrylic acid) (PEAA) alkylamide derivatives. The liposomal fusion was studied by use of fluorescence resonance energy transfer assay, particle size, fluorescent-photometer. The results indicated that the poly (2-ethylacrylic acid)-liposomes has very strong acidic induced fusion capability. Under acidic conditions, acid-sensitive polymer liposomes fused each other, the fusion closely related to the molecular weight of acid sensitivity polymer on the surface of liposomes. The acidic fusion of polymer-liposomes was dependent upon the lipids composition, the degree of fusion was reversely related to the cholesterol contents. Acid-en ci-nsitive polymer liposomes fused with erythrocyte ghosts. The liposomal fusion induced by acid-sensitive polymer associated with the increase of membrane permeability. The good acid-sensitivity of PEAA has been further demonstrated by membrane fusion in current experiments, and the liposomes prepared with lipid anchored-poly (2-ethylacrylic acid) were developeds s a potential pH sensitive delivery system.
Acrylates ; chemistry ; Alkylation ; Drug Carriers ; Drug Delivery Systems ; Erythrocyte Membrane ; metabolism ; Humans ; Hydrogen-Ion Concentration ; Lipids ; chemistry ; Liposomes ; chemistry ; Membrane Fusion ; Molecular Weight ; Particle Size ; Polymers ; Temperature

OBJECTIVETo observe effect of formula of removing both phlegm and blood stasis (TYTZ) in improving hemorheology and blood fat of mini-swine with coronary heart disease of phlegm-stasis cementation syndrome.

METHODThirty-six Chinese mini-swine were randomly divided to six groups: the normal control group, the model group, the Shujiangzhi group and TYTZ groups with doses of 2.0, 1.0 and 0.5 g x kg(-1), with six mice in each group. Except for the normal control group, all of other groups were fed with high-fat diet for 2 weeks. Interventional balloons are adopted to injure their left anterior descending artery endothelium. After the operation, they were fed with high-fat diet for 8 weeks to prepare the coronary heart disease model of phlegm-stasis cementation syndrome. In the 8th week after the operation and administration, the changes in hemorheological parameters, serum lipid level, myocardial ischemia level and range were observed.

RESULTCompared with the normal control group, the model group showed significant increase in serum TC, TG, LDL-C and VLDL-C levels (P < 0.01), whole blood viscosity under the shear rate of 5 s (-1) and 60 s (-1) (P < 0.01), and myocardial ischemia degree and range (P < 0.01). Compared with the model group, TYTZ groups revealed significant decrease in myocardial ischemia degree and range (P < 0.01), serum TC, TG, LDL-C and VLDL-C levels (P < 0.05 or P < 0.01) and whole blood viscosity under the shear rate of 5 s(-1) and 60 s(-1) (P < 0.05).

CONCLUSIONTYTZ could improve the abnormal hemorheology in Chinese mini-swine with coronary heart disease of phlegm-stasis cementation syndrome, and regulate serum lipid, with a certain efficacy for coronary heart disease of phlegm-stasis cementation syndrome.

Animals ; Coronary Disease ; blood ; metabolism ; physiopathology ; therapy ; Female ; Hemorheology ; Lipids ; blood ; Male ; Medicine, Chinese Traditional ; methods ; Mucous Membrane ; secretion ; Swine ; Swine, Miniature

Though high concentration of glucose can benefit the survival of lyophilized human red blood cells, the high concentration of glucose can result in serious damage of red blood cells. This study was aimed to investigate the inhibitory effect of trehalose on damage of red blood cells induced by high concentration of glucose. After incubation with the high concentration of glucose buffer containing different concentrations of trehalose for three hours at 37 degrees C, the phosphatidylserine exposure and the osmotic fragility of cells were analyzed by flow cytometry and the lipid peroxidation of membrane was evaluated by TBA method. The results showed that the high concentration of glucose could lead to phosphatidylserine exposure, osmotic fragility increase, and lipid peroxidation damage which were dependent on the glucose concentrations and incubation temperature. However, trehalose could effectively prevent the phosphatidylserine exposure, osmotic fragility increase, and lipid peroxidation damage induced by high concentration glucose. With increase of the trehalose concentrations. As the trehalose concentration increases, the phosphatidylserine exposure, maloni-aldehyde concentration and cell debris rate decreased gradually. In conclusion, the high concentration of glucose can lead to phosphatidylserine exposure, osmotic fragility increase, and lipid peroxidation damage of red blood cells. However, trehalose can inhibit the damaging effects of high concentration of glucose on red blood cells, which may be useful for the application of sugars to lyophilization of red blood cells.
Blood Preservation ; methods ; Erythrocyte Membrane ; drug effects ; metabolism ; Erythrocytes ; drug effects ; Flow Cytometry ; Glucose ; adverse effects ; Humans ; Lipid Peroxidation ; drug effects ; Membrane Lipids ; metabolism ; Osmotic Fragility ; drug effects ; Phosphatidylserines ; pharmacology ; Trehalose ; pharmacology

OBJECTIVETo study the effects of beta-amyloid peptide (Abeta) on cell membrane lipids and cholinergic receptors of human neuroblastoma cells.

METHODSHuman SH-SY5Y neuroblastoma cells were treated with different concentrations of Abeta(1-42) with and without pretreatment of vitamin E. MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] reduction, lipid peroxidation, protein oxidation and phospholipids were measured by spectrophotometry. Levels of cholesterol and unbiquinone were determined by high-performance liquid chromatography (HPLC). The numbers of cholinergic receptor binding sites were determined by receptor binding assay and the protein levels of nicotinic receptor alpha3 and alpha7 subunits were studied by Western blotting.

RESULTSSH-SY5Y cells showed decreased reduction rates of MMT and phospholipids, and increased lipid peroxidation and protein oxidation after exposure to Abeta (0.1 micromol/L) as compared to the control. The number of cholinergic receptor binding sites, the protein level of nicotinic receptor alpha3 and alpha7 subunits and the content of ubiquinone decreased in cells treated with high dose of Abeta (1 micromol/L). Although the level of cholesterol was not changed in any way, vitamin E partially prevented the neurotoxic effects of Abeta.

CONCLUSIONbeta-amyloid peptide reduces the level of cell membrane lipids and cholinergic receptors in human SH-SY5Y neuroblastoma cells, likely through the induction of an enhanced oxidative stress.

Amyloid beta-Peptides ; administration & dosage ; metabolism ; toxicity ; Cell Line, Tumor ; Cell Membrane ; metabolism ; Cholesterol ; metabolism ; Dose-Response Relationship, Drug ; Humans ; Lipid Peroxidation ; drug effects ; Malondialdehyde ; metabolism ; Membrane Lipids ; metabolism ; Neuroblastoma ; metabolism ; pathology ; Oxidative Stress ; drug effects ; Peptide Fragments ; administration & dosage ; metabolism ; toxicity ; Phospholipids ; metabolism ; Receptors, Nicotinic ; metabolism ; Ubiquinone ; metabolism ; Vitamin E ; metabolism ; pharmacology

OBJECTIVETo study the effect and mechanism of sodium ferulate (SF) in preventing and treating ozone (O3) induced lung oxidative injury in mice.

METHODSLung oxidative injury model mice were established by making them inhale O3. The activity of anti-oxidase and membranous microviscosity in epithelial cells in the lung of mice were determined, and the ultrastructural change of lung tissues was observed with electromicroscopy.

RESULTSActivities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were reduced, while membranous lipo-microviscosity significantly increased in the pulmonary epithelial cells of model mice, revealing ultrastructural change. These abnormal changes were reversed by SF treatment, which was manifested as the significantly raised activities of SOD and GSH-Px after treatment with high and moderate doses of SF, showing a significant difference compared with those in the model group (P<0.01). Membranous lipo-microviscosity basically approached that in the control group (P>0.05); electron microscopic examination showed a basically normal morphological structure of pulmonary epithelial cells, with the change in lung injury significantly milder than that in the model group.

CONCLUSIONO3 could induce oxidative injury of lungs in mice, and SF could enhance the anti-oxidation capacity of mice and scavenge the oxygen free radicals so as to alleviate the injury.

Animals ; Coumaric Acids ; pharmacology ; therapeutic use ; Glutathione Peroxidase ; metabolism ; Lung ; drug effects ; ultrastructure ; Lung Diseases ; chemically induced ; drug therapy ; enzymology ; prevention & control ; Male ; Membrane Lipids ; metabolism ; Mice ; Ozone ; adverse effects ; Superoxide Dismutase ; metabolism ; Viscosity ; drug effects

This study was performed to determine the accuracy of proton magnetic spectroscopy (1H-MRS) lipid peak as a noninvasive tool for quantitative in vivo detection of brain cell death. Seven day-old Sprague Dawley rats were subjected to 8% oxygen following a unilateral carotid artery ligation. For treatment, cycloheximide was given immediately after hypoxic ischemia (HI). Lipid peak was measured using 1H-MRS at 24 hr after HI, and then brains were harvested for fluorocytometric analyses with annexin V/propidium iodide (PI) and fluorescent probe JC-1, and for adenosine-5'-triphosphate (ATP) and lactate. Increased lipid peak at 1.3 ppm measured with 1H-MRS, apoptotic and necrotic cells, and loss of mitochondrial membrane potential (DeltaPsi) at 24 hr after HI were significantly improved with cycloheximide treatment. Significantly reduced brain ATP and increased lactate levels observed at 24 hr after HI showed a tendency to improve without statistical significance with cycloheximide treatment. Lipid peak at 1.3 ppm showed significant positive correlation with both apoptotic and necrotic cells and loss of DeltaPsi, and negative correlation with normal live cells. Lipid peak at 1.3 ppm measured by 1H-MRS might be a sensitive and reliable diagnostic tool for quantitative in vivo detection of brain cell death after HI.
Adenosine Triphosphate/*analysis ; Animals ; Animals, Newborn ; *Apoptosis ; Brain/metabolism/pathology ; Cycloheximide/pharmacology ; Hypoxia-Ischemia, Brain/*metabolism/*pathology ; Lactic Acid/*analysis ; Lipids/*analysis ; Magnetic Resonance Spectroscopy ; Membrane Potential, Mitochondrial ; Rats ; Rats, Sprague-Dawley