Hydrolysis of Parabenes by Extracts from Differing Layers of Human Skin

We have reported previously that the ceramidase from Pseudomonas aeruginosa AN17 isolated from a patient with atopic dermatitis requires detergents for hydrolysis of ceramide (Cer) [Okino, Tani, Imayama and Ito (1998) J. Biol. Chem. 273, 14368–14373]. In the present study, we report that some glycerophospholipids strongly activated the hydrolysis of Cer by Pseudomonas ceramidase in the absence of detergents. Among the glycerophospholipids tested, cardiolipin was most effective in stimulating hydrolysis of Cer followed by phosphatidic acid, phosphatidylethanolamine and phosphatidylglycerol, whereas phosphatidylcholine, lysophosphatidic acid and diacylglycerol were less effective. Interestingly, Staphylococcus aureus-derived lipids, which contain cardiolipin and phosphatidylglycerol as major lipid components, also strongly enhanced the hydrolysis of normal Cer, as well as the human skin-specific ω-hydroxyacyl Cer, by the enzyme in the absence of detergents. It was confirmed that several strains of P. aeruginosa, including AN17, secrete a significant amount of staphylolytic proteases to lyse S. aureus cells, resulting in the release of cardiolipin and phosphatidylglycerol. Since both P. aeruginosa and S. aureus are suspected of being present in microflora of atopic skin, we speculate that S. aureus-derived glycerophospholipids stimulate the hydrolysis of Cer in atopic skin by bacterial ceramidase.

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Chloride-insensitive, glycine–phenylalanine–naphthylamide hydrolysis at neutral pH in human skin fibroblasts

Biochemistry and Cell Biology ◽

10.1139/o86-105 ◽

1986 ◽

Vol 64 (8) ◽

pp. 772-781 ◽

Cited By ~ 1

Author(s):

Michael J. Doughty ◽

Eric I. Gruenstein

Keyword(s):

Human Skin ◽

Chloride Ion ◽

Substrate Affinity ◽

Human Skin Fibroblast ◽

Significant Activity ◽

Neutral Ph ◽

Fibroblast Line ◽

Cationic Detergents ◽

Dipeptidyl Aminopeptidase ◽

Hydrolysis Of

Crude lysosomal preparations from a cultured human skin fibroblast line were found to contain significant levels of a neutral pH hydrolase activity towards glycine – phenylalanine – β-naphthylamide (NA), a substrate normally used for the assay of lysosomal dipeptidyl aminopeptidase I. However, the activity was chloride ion insensitive, nonlatent, and inhibitable by cationic detergents and amino acids. Assays of substrate selectivity, relative substrate affinity, pH, and anion and cation sensitivity indicated the activity to be distinct from dipeptidyl aminopeptidases I (chloride-dependent hydrolysis of Pro-Phe-, Gly-Phe-, Gly-Arg-, and Pro-Arg-NA's at acid pH), II (Lys-Ala-NA hydrolysis), III (Arg-Arg-NA hydrolysis), and IV (Gly-Pro-NA hydrolysis). The lysosomal preparations also contained significant activity towards several amino acid – naphthylamides, notably Arg-NA. Only dipepidyl aminopeptidase I activity showed sensitivity to chloride anions, both dipeptidyl aminopeptidases I and II showed substantial latency, and none of the activities displayed a significant metal cation dependence.

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Intralysosomal hydrolysis of cholesterol esters of varying fatty acid composition in cultured human skin fibroblasts

Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism ◽

10.1016/0005-2760(78)90162-5 ◽

1978 ◽

Vol 530 (3) ◽

pp. 420-427 ◽

Cited By ~ 18

Author(s):

Y. Stein ◽

G. Halperin ◽

O. Stein

Keyword(s):

Fatty Acid Composition ◽

Fatty Acid ◽

Human Skin ◽

Acid Composition ◽

Skin Fibroblasts ◽

Cholesterol Esters ◽

Human Skin Fibroblasts ◽

Hydrolysis Of

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Fine Structural Localization of Acyltransferases Involved in Lipid Synthesis in Intestinal Mucosa.

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100067261 ◽

1970 ◽

Vol 28 ◽

pp. 54-55

Author(s):

R. J. Barrnett ◽

J. A. Higgins

Keyword(s):

Smooth Endoplasmic Reticulum ◽

Lipid Synthesis ◽

Mucosal Cell ◽

Structural Localization ◽

Morphological Studies ◽

Mucosal Cells ◽

Initial Appearance ◽

Sh Group ◽

Hydrolysis Of ◽

Intestinal Mucosal Cells

The main products of intestinal hydrolysis of dietary triglycerides are free fatty acids and monoglycerides. These form micelles from which the lipids are absorbed across the mucosal cell brush border. Biochemical studies have indicated that intestinal mucosal cells possess a triglyceride synthesising system, which uses monoglyceride directly as an acylacceptor as well as the system found in other tissues in which alphaglycerophosphate is the acylacceptor. The former pathway is used preferentially for the resynthesis of triglyceride from absorbed lipid, while the latter is used mainly for phospholipid synthesis. Both lipids are incorporated into chylomicrons. Morphological studies have shown that during fat absorption there is an initial appearance of fat droplets within the cisternae of the smooth endoplasmic reticulum and that these subsequently accumulate in the golgi elements from which they are released at the lateral borders of the cell as chylomicrons.We have recently developed several methods for the fine structural localization of acyltransferases dependent on the precipitation, in an electron dense form, of CoA released during the transfer of the acyl group to an acceptor, and have now applied these methods to a study of the fine structural localization of the enzymes involved in chylomicron lipid biosynthesis. These methods are based on the reduction of ferricyanide ions by the free SH group of CoA.

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A web-like network of type vi collagen in human skin is revealed by immuno-electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103978 ◽

1988 ◽

Vol 46 ◽

pp. 382-383

Author(s):

Douglas R. Keene ◽

Robert W. Glanville ◽

Eva Engvall

Keyword(s):

Electron Microscopy ◽

Monoclonal Antibody ◽

Human Skin ◽

Basement Membranes ◽

Primary Antibody ◽

Fat Cells ◽

Secondary Antibody ◽

Type Vi Collagen ◽

Dermal Matrix ◽

Immuno Electron Microscopy

A mouse monoclonal antibody (5C6) prepared against human type VI collagen (1) has been used in this study to immunolocalize type VI collagen in human skin. The enbloc method used involves exposing whole tissue pieces to primary antibody and 5 nm gold conjugated secondary antibody before fixation, and has been described in detail elsewhere (2).Biopsies were taken from individuals ranging in age from neonate to 65 years old. By immuno-electron microscopy, type VI collagen is found to be distributed as a fine branching network closely associated with (but not attached to) banded collagen fibrils containing types I and III collagen (Fig. 1). It appears to enwrap fibers, to weave between individual fibrils within a fiber, and to span the distance separating fibers, creating a “web-like network” which entraps fibers within deep papillary and reticular dermal layers (Fig. 2). Relative to that in the dermal matrix, the concentration of type VI collagen is higher around endothelial basement membranes limiting the outer boundaries of nerves, capillaries, and fat cells (Fig. 3).

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Lattice imaging and pore structure of β ferric oxyhydroxide

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100108465 ◽

1978 ◽

Vol 36 (1) ◽

pp. 264-265

Author(s):

T. Baird ◽

J.R. Fryer ◽

S.T. Galbraith

Keyword(s):

Electron Microscopy ◽

Room Temperature ◽

Bulk Material ◽

Model Structure ◽

Bulk Crystals ◽

Lattice Imaging ◽

Thin Sections ◽

Ferric Oxyhydroxide ◽

Resolution Electron ◽

Hydrolysis Of

Introduction Previously we had suggested (l) that the striations observed in the pod shaped crystals of β FeOOH were an artefact of imaging in the electron microscope. Contrary to this adsorption measurements on bulk material had indicated the presence of some porosity and Gallagher (2) had proposed a model structure - based on the hollandite structure - showing the hollandite rods forming the sides of 30Å pores running the length of the crystal. Low resolution electron microscopy by Watson (3) on sectioned crystals embedded in methylmethacrylate had tended to support the existence of such pores.We have applied modern high resolution techniques to the bulk crystals and thin sections of them without confirming these earlier postulatesExperimental β FeOOH was prepared by room temperature hydrolysis of 0.01M solutions of FeCl3.6H2O, The precipitate was washed, dried in air, and embedded in Scandiplast resin. The sections were out on an LKB III Ultramicrotome to a thickness of about 500Å.

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Effect of Acetone and Kerosene on Skin Ultrastructure

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100093717 ◽

1972 ◽

Vol 30 ◽

pp. 92-93

Author(s):

A. P. Lupulescu ◽

H. Pinkus ◽

D. J. Birmingham

Keyword(s):

Electron Microscopy ◽

Human Skin ◽

Osmium Tetroxide ◽

Human Epidermis ◽

Ultrastructural Changes ◽

Chemical Agents ◽

Skin Ultrastructure ◽

Volar Surface

Our laboratory is engaged in the study of the effect of different chemical agents on human skin, using electron microscopy. Previous investigations revealed that topical use of a strong alkali (NaOH 1N) or acid (HCl 1N), induces ultrastructural changes in the upper layers of human epidermis. In the current experiments, acetone and kerosene, which are primarily lipid solvents, were topically used on the volar surface of the forearm of Caucasian and Negro volunteers. Skin specimens were bioptically removed after 90 min. exposure and 72. hours later, fixed in 3% buffered glutaraldehyde, postfixed in 1% phosphate osmium tetroxide, then flat embedded in Epon.

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Changes in corneocyte element concentrations occur in skin inner stratum corneum

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100134326 ◽

1990 ◽

Vol 48 (2) ◽

pp. 146-147

Author(s):

R. R. Warner

Keyword(s):

Stratum Corneum ◽

Human Skin ◽

Element Concentration ◽

Skin Barrier ◽

Barrier Properties ◽

Brick Wall ◽

Inorganic Elements ◽

Dry Skin ◽

Skin Biopsies ◽

Intercellular Lipid

Keratinocytes undergo maturation during their transit through the viable layers of skin, and then abruptly transform into flattened, anuclear corneocytes that constitute the cellular component of the skin barrier, the stratum corneum (SC). The SC is generally considered to be homogeneous in its structure and barrier properties, and is often shown schematically as a featureless brick wall, the “bricks” being the corneocytes, the “mortar” being intercellular lipid. Previously we showed the outer SC was not homogeneous in its composition, but contained steep gradients of the physiological inorganic elements Na, K and Cl, likely originating from sweat salts. Here we show the innermost corneocytes in human skin are also heterogeneous in composition, undergoing systematic changes in intracellular element concentration during transit into the interior of the SC.Human skin biopsies were taken from the lower leg of individuals with both “good” and “dry” skin and plunge-frozen in a stirred, cooled isopentane/propane mixture.

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