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

Animals ; Cell Membrane ; chemistry ; metabolism ; Humans ; Membrane Proteins ; chemistry ; metabolism ; Protein Structure, Secondary

Spermatogenesis is a complex developmental process in which a diploid progenitor germ cell transforms into highly specialized spermatozoa. During spermatogenesis, membrane remodeling takes place, and cell membrane permeability and liquidity undergo phase-specific changes, which are all associated with the alteration of membrane lipids. Lipids are important components of the germ cell membrane, whose volume and ratio fluctuate in different phases of spermatogenesis. Abnormal lipid metabolism can cause spermatogenic dysfunction and consequently male infertility. Germ cell membrane lipids are mainly composed of cholesterol, phospholipids and glycolipids, which play critical roles in cell adhesion and signal transduction during spermatogenesis. An insight into the correlation of membrane lipids with spermatogenesis helps us to better understand the mechanisms of spermatogenesis and provide new approaches to the diagnosis and treatment of male infertility.
Cell Adhesion ; Cell Membrane ; chemistry ; Cholesterol ; chemistry ; Glycolipids ; chemistry ; Humans ; Infertility, Male ; Male ; Membrane Lipids ; chemistry ; Phospholipids ; chemistry ; Signal Transduction ; Spermatogenesis ; Spermatozoa ; cytology

The aim of this research is to investigate the effects of paeoniflorin and menthol on the physiological function of Calu-3 cell membrane during the transport of puerarin. Calu-3 cell was used as the cell model to simulate nasal mucosa tissues, and the cell membrane fluidity, Na⁺-K⁺-ATPase activity and Ca²⁺-ATPase activity were detected by fluorescence recovery after photobleaching(FRAP) and ultramicro enzyme activity testing, in order to explore the mechanism of compatible drugs on promoting puerarin transport. The results showed that when puerarin associated with low, middle and high concentration of menthol or both paeoniflorin and menthol, the fluorescence recovery rate was increased significantly, while Na⁺-K⁺-ATPase activity had no significant change and Ca²⁺-ATPase activity was enhanced significantly as compared with puerarin alone. Therefore, it was concluded that menthol had the abilit of promoting the transport and the mechanism might be related to increasing membrane fluidity and activating Ca²⁺-ATPase.
Calcium-Transporting ATPases ; metabolism ; Cell Line, Tumor ; Cell Membrane ; Glucosides ; chemistry ; Humans ; Isoflavones ; metabolism ; Membrane Fluidity ; Menthol ; chemistry ; Monoterpenes ; chemistry ; Sodium-Potassium-Exchanging ATPase ; metabolism

OBJECTIVESTo investigate the localization and positive percentage of progesterone receptor (PR) on the human sperm surface.

METHODSAfter in vitro capacitation, progesterone binding sites on the sperm were quantitatively analyzed by fluorescence microscopy and flow cytometry using fluorescein isothiocyanate-labeled bovine serum albumin-progesterone complex (P-BSA-FITC).

RESULTSThe spermatozoa stained by P-BSA-FITC mainly showed two labeling patterns, with the green fluorescence on the whole acrosomal region or the equatorial acrosomal region only and the stainless postacrosomal and tail regions. The percentage of progesterone-binding sperm was (30.2 +/- 2.4)%.

CONCLUSIONSThere is selective expression of PR on the human sperm acrosome surface.

Adult ; Cell Membrane ; chemistry ; Flow Cytometry ; Humans ; Male ; Microscopy, Fluorescence ; Receptors, Progesterone ; analysis ; Spermatozoa ; chemistry

OBJECTIVETo investigate the progesterone-binding site on the normal fertile human sperm membrane after 2 hours of in vitro capacitation.

METHODSViable spermatozoa were selected by a swim-up method. After 2 hours of in vitro capacitation, multipoint saturation binding experiments were performed. Sperm suspension and increasing concentrations of progesterone-11alpha-glucuronide-[125I] iodotyramine (125I-P) were added to 7 total binding tubes respectively, and equal amounts of sperm suspension and 125I-P were added to another 7 corresponding non-specific binding tubes in the presence of 10 micromol/L progesterone. After incubation for 1 hour at 4 degrees C, the radioactivity of both the tubes and the pellets after centrifugation was measured respectively. The equilibrium dissociation constant (Kd) and maximum binding capacity (Bmax) were calculated using the mathematical model of single site multi-point saturation method of Scatchard function and least-squares regression.

RESULTSKd was (0.61 +/- 0.04) nmol/L and Bmax was (830 +/- 344) sites/cell. The significance test of the regression equation indicated that r = -0.980, P < 0.01.

CONCLUSIONThere is a high affinity and low capacity binding site for the progesterone (progesterone receptor) on the normal fertile human sperm membrane.

Adult ; Cell Membrane ; chemistry ; Humans ; Male ; Progesterone ; Radioligand Assay ; Receptors, Progesterone ; analysis ; 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

This paper was aimed to study conserved motifs of voltage sensing proteins (VSPs) and establish a voltage sensing model. All VSPs were collected from the Uniprot database using a comprehensive keyword search followed by manual curation, and the results indicated that there are only two types of known VSPs, voltage gated ion channels and voltage dependent phosphatases. All the VSPs have a common domain of four helical transmembrane segments (TMS, S1-S4), which constitute the voltage sensing module of the VSPs. The S1 segment was shown to be responsible for membrane targeting and insertion of these proteins, while S2-S4 segments, which can sense membrane potential, for protein properties. Conserved motifs/residues and their functional significance of each TMS were identified using profile-to-profile sequence alignments. Conserved motifs in these four segments are strikingly similar for all VSPs, especially, the conserved motif [RK]-X(2)-R-X(2)-R-X(2)-[RK] was presented in all the S4 segments, with positively charged arginine (R) alternating with two hydrophobic or uncharged residues. Movement of these arginines across the membrane electric field is the core mechanism by which the VSPs detect changes in membrane potential. The negatively charged aspartate (D) in the S3 segment is universally conserved in all the VSPs, suggesting that the aspartate residue may be involved in voltage sensing properties of VSPs as well as the electrostatic interactions with the positively charged residues in the S4 segment, which may enhance the thermodynamic stability of the S4 segments in plasma membrane.
Arginine ; chemistry ; Aspartic Acid ; chemistry ; Cell Membrane ; physiology ; Conserved Sequence ; Ion Channel Gating ; Ion Channels ; chemistry ; Membrane Potentials ; Protein Structure, Tertiary

OBJECTIVETo investigate the Raman spectral characteristics of oral squamous cell carcinoma, high-grade epithelial dysplasia and normal mucosa.

METHODSFifty- six fresh samples of oral carcinoma, 50 of high-grade epithelial dysplasia and 32 of normal mucosa were collected. The i-Raman spectrometer with an optical fiber tube was applied to acquire Raman spectrum. The diagnostic model established by principle component analysis (PCA) and discriminant function analysis (DFA) was used to analyze and classify the spectra of different samples.

RESULTSThere were significant differences among the Raman spectra of these samples. Compared with the spectra of normal mucosa, the spectra of oral carcinoma and dysplasia showed strong peaks which were contributed to nucleic acids, proteins and lipids. The diagnostic models established by PCA-DFA could successfully classify these Raman spectra of different samples with a high accuracy of 96.4% (133/138). The model was evaluated by 'Leave one out' cross-validation and reached a high accuracy of 92.8% (128/138).

CONCLUSIONSThe proliferation and metabolism of oral squamous cell carcinoma and epithelial high-grade dysplasia are more active than normal mucosa. The diagnostic models established by PCA-DFA can classify these Raman spectra of different samples with a high accuracy.

Carcinoma, Squamous Cell ; chemistry ; pathology ; Discriminant Analysis ; Epidermis ; chemistry ; pathology ; Humans ; Mouth Mucosa ; chemistry ; Mouth Neoplasms ; chemistry ; pathology ; Mucous Membrane ; chemistry ; Principal Component Analysis ; Spectrum Analysis, Raman

As a novel bioaffinity chromatography technique, cell membrane chromatography (CMC) was first established by Professor He in 1996, with which combined high performance liquid chromatography, cytobiology, and receptor pharmacology. The cell membrane stationary phase (CMSP) consists of porous silica coated with active cell membranes. By immersing silica into a suspension of cell membranes, the whole surface of silica was covered by the cell membranes. In CMC, the interaction of drugs or compounds with the immobilized cell membrane or its receptors is investigated using liquid chromatography. In general, with the aim to provide scientific foundation for further development and application, this paper mainly focuses on the characteristics of the cell membrane stationary phase (CMSP), the CMC analytical system, and its applications in traditional Chinese medicines (TCMs) about CMC. With the development of CMC, the breakthrough progress of it in studying active components of TCMs field is expectant.
Animals ; Cell Membrane ; chemistry ; Chromatography, Affinity ; methods ; Drugs, Chinese Herbal ; analysis ; Humans ; Medicine, Chinese Traditional ; methods