In vitro chondrogenesis of Wharton's jelly mesenchymal stem cells in hyaluronic acid-based hydrogels.

BACKGROUND: In this study, we evaluated the usefulness of two commercially available hyaluronic acid-based hydrogels, HyStem and HyStem-C, for the cultivation of Wharton's jelly mesenchymal stem cells (WJ-MSCs) and their differentiation towards chondrocytes. METHODS: The WJ-MSCs were isolated from umbilical cord Wharton's jelly using the explant method and their immunophenotype was evaluated via flow cytometry analysis. According to the criteria established by the International Society for Cellular Therapy, they were true MSCs. We assessed the ability of the WJ-MSCs and chondrocytes to grow in three-dimensional hydrogels and their metabolic activity. Chondrogenesis of WJ-MSCs in the hydrogels was determined using alcian blue and safranin O staining and real-time PCR evaluation of gene expression in the extracellular matrixes: collagen type I, II, III and aggrecan. RESULTS: Chondrocytes and WJ-MSCs cultured in the HyStem and HyStem-C hydrogels adopted spherical shapes, which are characteristic for encapsulated cells. The average viability of the WJ-MSCs and chondrocytes in the HyStem hydrogels was approximately 67 % when compared with the viability in 2D culture. Alcian blue and safranin O staining revealed intensive production of proteoglycans by the cells in the HyStem hydrogels. Increased expression of collagen type II and aggrecan in the WJ-MSCs cultured in the HyStem hydrogel in the presence of chondrogenic medium showed that under these conditions, the cells have a high capacity to differentiate towards chondrocytes. The relatively high viability of WJ-MSCs and chondrocytes in both HyStem hydrogels suggests the possibility of their use for chondrogenesis. CONLUSIONS: The results indicate that WJ-MSCs have some degree of chondrogenic potential in HyStem and HyStem-C hydrogels, showing promise for the engineering of damaged articular cartilage.

Changes in expression of cartilaginous genes during chondrogenesis of Wharton's jelly mesenchymal stem cells on three-dimensional biodegradable poly(L-lactide-co-glycolide) scaffolds.

BACKGROUND: In cartilage tissue regeneration, it is important to develop biodegradable scaffolds that provide a structural and logistic template for three-dimensional cultures of chondrocytes. In this study, we evaluated changes in expression of cartilaginous genes during in vitro chondrogenic differentiation of WJ-MSCs on PLGA scaffolds. METHODS: The biocompatibility of the PLGA material was investigated using WJ-MSCs by direct and indirect contact methods according to the ISO 10993-5 standard. PLGA scaffolds were fabricated by the solvent casting/salt-leaching technique. We analyzed expression of chondrogenic genes of WJ-MSCs after a 21-day culture. RESULTS: The results showed the biocompatibility of PLGA and confirmed the usefulness of PLGA as material for fabrication of 3D scaffolds that can be applied for WJ-MSC culture. The in vitro penetration and colonization of the scaffolds by WJ-MSCs were assessed by confocal microscopy. The increase in cell number demonstrated that scaffolds made of PLGA copolymers enabled WJ-MSC proliferation. The obtained data showed that as a result of chondrogenesis of WJ-MSCs on the PLGA scaffold the expression of the key markers collagen type II and aggrecan was increased. CONCLUSIONS: The observed changes in transcriptional activity of cartilaginous genes suggest that the PLGA scaffolds may be applied for WJ-MSC differentiation. This primary study suggests that chondrogenic capacity of WJ-MSCs cultured on the PLGA scaffolds can be useful for cell therapy of cartilage.

ANTIPROLIFERATIVE ACTIVITY OF NOVEL ACETYLENIC DERIVATIVES OF BETULIN AGAINST G-361 HUMAN MELANOMA CELLS.

Acetylenic derivatives of betulin were tested in vitro for their antiproliferative activity against G-361 human melanoma cells. Two types of betulin derivatives were studied: monoesters, obtained by modification of the hydroxyl group at C-28 position, and diesters modified at both C-28 and C-3 positions. To assess cell proliferation, a colorimetric sulforhodamine B based method was used. All the tested monoesters inhibited cellular growth and 28-O-propynoylbetulin showed the strongest cytotoxic effect. Esterification of the C-3 hydroxyl group of the molecule abolished its growth inhibitory activity.

EFFECTS OF 300 mT STATIC MAGNETIC FIELD ON IL-8 SECRETION IN NORMAL HUMAN COLON MYOFIBROBLASTS.

Intestinal subepithelial myofibroblasts play a crucial role in the growth and development of the intestine. Colitis, small bowel injury, gastric ulcer disease and inflammatory bowel disease (IBD) accompany the increase in the count of activated myofibroblasts. In the last few years, the increasing production of electromagnetic (EMF) and static magnetic (SMF) fields due to the expanding use of electronic devices in everyday life, has led to a number of studies on the effects of these fields on living organisms. Because of its anti-inflammatory properties, EMF therapy may be of medical use as an IBD treatment. This mechanism has not been elucidated yet. In the present work normal human colon myofibroblasts were exposed to SMF with a flux density of 300 mT for 96 h and then the cells were cultured for 24 and 48 h with 25 mM sodium butyrate (NaB) and 10 mM 5-aminosalicylic acid (5-ASA) in either the presence or absence of SMF. Tumor necrosis factor α (TNF-α)--dependent IL-8 secretion was determined with ELISA kit. Cell viability was determined with XTT assay. It was shown that SMF has no effect on TNF-α--dependent IL-8 secretion in control cells and in cells cultured in the presence of 5-ASA and NaB.

THE EFFECT OF SULFASALAZINE AND 5-AMINOSALICYLIC ACID ON THE SECRETION OF INTERLEUKIN 8 BY HUMAN COLON MYOFIBROBLASTS.

Sulfasalazine (SAS) and its therapeutically active derivative--5-aminosalicylic acid (5-ASA) are used in the treatment of inflammatory bowel disease. 5-ASA mechanism of action on the one hand, involves the inhibition of the cyclooxygenase and lipoxygenase activity, and thus decrease of synthesis of prostaglandins, leukotrienes and free radicals, on the other hand, the suppression of the immune response in the intestinal mucosa. Myofibroblasts, which are located just below the basement membrane, are important element of the mucosa. Due to its secretory activity they may interact with other cells, including epithelial cells. Examining SAS and 5-ASA cytotoxic properties on human normal, colon subepithelial myofibroblasts (CSEMF) it was found that the first of these compounds in a concentration of 1 mM significantly reduced the number of these cells as compared to the control, while the latter exhibited an action at the 5-fold higher concentration (5 mM). Moreover, SAS concentration greater than 0.25 mM reduced IL-8 secretion by CSEMF, and 5-ASA had no effect in the tested range of concentrations, i.e., up to 7.5 mM.

Influence of betulin and 28-O-propynoylbetulin on proliferation and apoptosis of human melanoma cells (G-361).

INTRODUCTION: Pentacyclic triterpenes are a group of compounds known to have anticancer activity. One of the best characterized triterpenes is betulin, which can be isolated from bark of birch trees and modified into new compounds with various interesting medical properties. Betulin is involved in activation of the caspase cascade and promotes cell death. The aim of the study was to investigate the effect of betulin and its acetylenic derivative, 28-O-propynoylbetulin, on proliferation and apoptosis in a human melanoma cell line. MATERIALS AND METHODS: The G-361 melanoma cell line was used. To evaluate growth arrest and caspase-3 activity, cells were treated with betulin and its derivative at a wide range of concentrations from 0.1 to 10 µg/mL. RESULTS: Betulin and 28-O-propynoylbetulin inhibited cell proliferation in a concentration-dependent manner. The cell cycle analysis revealed an increase of the sub-G1 cell fraction (representing dead cells) after incubation of cells with betulin and 28-O-propynoylbetulin. The observed cytotoxic effects were more pronounced for 28-O-propynoylbetulin. Activity of caspase-3 in 28-O-propynoylbetulin treated cells was nearly 2-fold greater compared to cells incubated with betulin. DISCUSSION: Our results show that betulin and 28-O-propynoylbetulin were effective in inhibition of cell growth and induction of apoptosis in a human melanoma cell line. The addition of the propynoyl group at the C-28 hydroxyl group of betulin led to a greater proapoptotic and antiproliferative effect in comparison to unmodified betulin. These observations suggest that the obtained derivative is a potent anti-melanoma agent.

Effect of GLY-HIS-LYS and its copper complex on TGF-ß secretion in normal human dermal fibroblasts.

Transforming growth factor ß (TGF-ß) is a cytokine involved in a wide variety of biological process- es such as cell growth, differentiation and proliferation, apoptosis and regulation of the immune response. It has an important role in wound healing process, fibrosis and scar tissue formation. Similarly to TGF-ß1, insulin growth factor (IGF) family is expressed locally in response to tissue injury. Treatment of dermal fibroblasts with IGF-1 caused a substantial induction of TGF-ß1 mRNA. Not a great deal of research so far has focused on IGF-2. Much attention has been focused on the tripeptides such as Gly-His-Lys (GHK) and their copper complexes, which have a high activity and good skin tolerance. Recent data suggest that their physiological role has been related to the process of wound healing, tissue repair and skin inflammation. In the present study, the influence of 1 nM solutions of GHK, GHK-Cu and CuCl2, on IGF-2-dependent TGF-ß1 secretion in normal human dermal fibroblasts cells was investigated. Fibroblasts were cultured in 24-well plates. Total TGF-ß1 pro- tein was evaluated using the ELISA kit. The Bradford reagent was used to determine the total quantity of cel- lular protein. Treatment of fibroblasts with 100 ng/mL IGF-2 resulted in a significant increase in TGF-ß1 secretion. GHK and its copper complex and free copper ions decreased IGF-2-dependent TGF-ß1 secretion. Our observations provide some new information on the potential use of that peptide contained in cosmetics to treat and prevent the formation of hypertrophic scars.

Antiproliferative effect of valproic acid and 5,7-dimethoxycoumarin against A2058 human melanoma cells.

Melanoma is one of the most malignant tumors of a dangerous high incidence and high metastatic potential. It grows quickly and in an advanced stage is resistant to radio-, chemo- and immunotherapy, which makes it difficult to cure. Therefore, research efforts are focused on the development of new therapeutics or chemopreventive strategies. The aim of the study was to investigate whether the valproic acid and 5,7-dimethoxycoumarin have an antiproliferative activity against A2058 human melanoma cell line. Investigated compounds inhibited the proliferation of cells, however, no synergistic effect of their co-administration was observed.

Effect of valproic acid on the proliferation and apoptosis of the human melanoma G-361 cell line.

Melanoma malignant is characterized by a high malignancy and low susceptibility to treatment. Due to these properties, there is a growing interest in compounds that would have the ability to inhibit proliferation, induce differentiation of tumor cells and initiate the apoptotic pathway. In vitro and in vivo research indicate that valproic acid (a histone deacetylase inhibitor) may have anti-cancer properties. In our study, the role of VPA on proliferation and apoptosis in G-361 human melanoma cell line was examined. Obtained results indicated that administration of VPA at concentrations above ≥ 1 mM led to significant inhibition of cell growth. Simultaneously, it was observed that VPA at higher concentrations (5 and 10 mM) caused an increase in caspase-3 activity.

Polyunsaturated fatty acids potentiate cytotoxicity of cisplatin in A549 cells.

In normal and tumor cells, polyunsaturated fatty acids (PUFAs) act as intracellular second messengers, which play a role in signaling, proliferation and cell death. PUFAs have selective tumoricidal action and may alter sensitivity of tumor cells to cisplatin (CDDP), a commonly used anticancer agent. The aim of this study was to evaluate the influence of arachidonic acid (AA, 20:4 n-6), eicosapentaenoic acid (EPA, 20:5 n-3), docosahexaenoic acid (DHA, 22:6 n-3) and CDDP on autophagy and apoptosis in A549 human lung adenocarcinoma cells. Viability of A549 cells treated with CDDP and PUFAs was measured using the XTT tetrazolium salt based assay. Caspase-3/7 activity was estimated using ApoTox-Glo kit (Promega). Autophagic vac- uoles were detected by Cyto-ID Autophagy Detection Kit (Enzo). The results were compared to control cultures maintained in the absence of CDDP and PUFAs. PUFAs, in particular EPA and DHA, added to the cultivation medium, increased the antitumor activity of CDDP in A549 cells in a concentration dependent manner. In case of AA this effect was observed at the highest of the concentrations tested only (100 µM). Both, EPA and DHA, but not AA, significantly increased the amount of autophagic vacuoles and induced caspase-3/7 activity. The obtained results suggest that the antiproliferative effect of CDDP in A549 cells can be enhanced by AA and in particular by EPA and DHA through their influence on autophagic and apoptotic cell death. It is likely that BPA and DHA incorporated to the tumor cells may improve outcomes in lung cancer patients.

Polyunsaturated fatty acids inhibit melanoma cell growth in vitro.

Human malignant melanoma is a highly aggressive and incurable cancer due to intrinsic resistance to apoptosis and reprogramming proliferation and survival pathways during progression. Numerous studies, including our own, linked arachidonic acid (AA, 20:4 n-6), eicosapentaenoic acid (EPA, 20:5 n-3), and docosahexaenoic acid (DHA, 22:6 n-3) supplementation to induction of apoptosis and decreased proliferation of various cancer cells. The cytotoxic effects result from lipid peroxidation and formation of reactive oxygen species (ROS), which modify proteins and nucleic acids. DNA damage by ROS causes mutations and genomic instability, leading to uncontrolled proliferation or cell death. In the present work, four human melanoma cell lines differing in origin, doubling time, metastatic potential, and melanin content (A375, A2058, G361, and C32) were exposed to AA, EPA or DHA added into culture media in the concentrations ranging from 0 (control) to 100 mM. After 24 h incubation cytotoxicity of the analyzed acids was determined with TOX-2 (In Vitro Toxicology Assay Kit XTT Based, TOX-2, Sigma) test. The oxidative protein modifications were measured using Aldehyde Site (DNA and Protein) Detection Kit (Cayman). All the acids tested showed marked inhibition of cell proliferation. The observed effects were statistically significant and depended on the concentration. Decrease of proliferation, associated by oxidative protein and DNA damage (measured as aldehyde sites in cells), was observed for EPA and DHA (50 mM and 100 mM) in A375, A2058, and G361 cells. In case of C32 cell line, which is amelanotic melanoma, EPA and DHA inhibited cell proliferation at 100 mM only. The effect of DHA was more pronounced. AA did not show its antiproliferative action in this cell line. The obtained results suggest that antiproliferative effects of the fatty acids in cultured human melanoma cells depend on the type of acid, its concentration and may be diverse when different melanoma cell lines are used.

Evaluation of melanogenesis in A-375 melanoma cells treated with 5,7-dimethoxycoumarin and valproic acid.

Malignant melanoma (melanoma malignum) is one of the most dangerous types of tumor. It is very difficult to cure. In recent years, a lot of attention has been given to chemoprevention. This method uses natural and synthetic compounds to interfere with and inhibit the process of carcinogenesis. In this study, a new treatment strategy was proposed consisting of a combination of 5,7-dimethoxycoumarin (DMC), an activator of melanogenesis, and valproic acid (VPA), a well-known drug that is one of the histone deacetylase inhibitors (HDACis). In conjunction with 1 mM VPA, all of the tested concentrations of DMC (10-150 µM) significantly decreased the proliferation of A-375 cells. VPA and DMC also induced the synthesis of melanin and the formation of dendrite and star-shaped cells. Tyrosinase gene expression and tyrosinase activity significantly increased in response to VPA treatment. Pyrolysis with gas chromatography and mass spectrometry (Py-GC/MS) was used to investigate the structure of the isolated melanin. This showed that the quantitative and qualitative components of melanin degradation products are dependent on the type of applied melanogenesis inductor. Products derived from eumelanin were detected in the pyrolytic profile of melanin isolated from A-375 cells stimulated with DMC. Thermal degradation of melanin isolated from melanoma cells after exposure to VPA or a mixture of VPA and DMC revealed the additional presence of products derived from pheomelanin.

The chemical composition of endotoxin isolated from intestinal strain of Desulfovibrio desulfuricans.

Desulfovibrio desulfuricans anaerobes are constituents of human alimentary tract microflora. There are suggestions that they take part in the pathogenesis of periodontitis and some gastrointestinal inflammatory disorders, such as ulcerative colitis or Crohn's disease. Endotoxin is one of Gram-negative bacteria cellular components that influence these microorganisms pathogenicity. Endotoxin is a lipid-polisaccharide heteropolymer consisting of three elements: lipid A, core oligosaccharide, and O-specific polysaccharide, also called antigen-O. The biological activity of lipopolysaccharide (LPS) is determined by its structure. In this study, we show that rhamnose, fucose, mannose, glucose, galactose, heptose, and 2-keto-3-deoxyoctulosonic acid (Kdo) are constituents of D. desulfuricans endotoxin oligosaccharide core and O-antigen. Lipid A of these bacteria LPS is composed of glucosamine disaccharide substituted by 3-acyloxyacyl residues: ester-bound 3-(dodecanoyloxy)tetradecanoic, 3-(hexadecanoyloxy)tetradecanoic acid, and amide-bound 3-(tetradecanoyloxy)tetradecanoic acid.

Evaluation of melanogenesis in A-375 cells in the presence of DMSO and analysis of pyrolytic profile of isolated melanin.

The increase of a skin malignant melanoma (melanoma malignum) incidence in the world has been observed in recent years. The tumour, especially in advanced stadium with metastases, is highly resistant to conventional treatment. One of the strategies is to modulate melanogenesis using chemical compounds. In this study, the processes of differentiation and melanogenesis induced by dimethylsulfoxide (DMSO) in human melanoma cells (A-375) were investigated. Natural melanin isolated from A-375 melanoma cell line treated with 0.3% DMSO was analyzed by pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) method. The products derived from pheomelanin have not been stated in the pyrolytic profile of analyzed melanin. Within all products derived from eumelanins, 1,2-benzenediol has been predominated. It has been shown that in the melanoma cells stimulated with 0.3% and 1% DMSO, the increase of transcriptional activity of the tyrosinase gene took place. It was accompanied by the rise of tyrosinase activity and an accumulation of melanin in the cells. The better knowledge about the structure of melanins can contribute to establish the uniform criteria of malignant melanoma morbidity risk.

Effect of Gly-Gly-His, Gly-His-Lys and their copper complexes on TNF-alpha-dependent IL-6 secretion in normal human dermal fibroblasts.

Cosmeceuticals represent a marriage between cosmetics and pharmaceuticals. There are numerous cosmeceutically active products which can be broadly classified into the following categories: antioxidants, oligopeptides, growth factors and pigment lightning agents. Much attention has been focused on the tripeptides such as Gly-His-Lys (GHK) and Gly-Gly-His (GGH) and their copper complexes, which have a high activity and good skin tolerance. Recent data suggested their physiological role in process of wound healing, tissue repair and skin inflammation. The mechanism of anti-inflammatory properties of these peptides is not clear. The aim of the study was evaluation of influence of two peptides GGH. GHK and their copper complexes and saccharomyces/copper ferment (Oligolides Copper) on secretion of pro-inflammatory IL-6 in normal human dermal fibroblasts NHDF cell line. IL-6 was evaluated using the ELISA kit. GGH, GHK, CuCl2 and their copper complexes decreased TNF-alpha-dependent IL-6 secretion in fibroblasts. IL-6 is crucial for normal wound healing, skin inflammation and UVB-induced erythema. Because of the anti-inflammatory properties, the copper-peptides could be used on the skin surface instead of corticosteroids or non-steroidal anti-inflammatory drugs, which have more side effects. Our observations provide some new information about the role of these tripeptides in skin inflammation.

Examination by EPR spectroscopy of free radicals in melanins isolated from A-375 cells exposed on valproic acid and cisplatin.

Drug binding by melanin biopolymers influence the effectiveness of the chemotherapy, radiotherapy and photodynamic therapy. Free radicals of melanins take part in formation of their complex with drugs. The aim of this work was to determine the effect of the two compounds: valproic acid (VPA) and cisplatin (CPT) on free radicals properties of melanin isolated from A-375 melanoma cells. Free radicals were examined by an X-band (9.3 GHz) electron paramagnetic resonance (EPR) spectroscopy. EPR spectra were measured for the model synthetic eumelanin - DOPA-melanin, the melanin isolated from the control A-375 cells and these cells treated by VPA, CPT and both VPA and CPT. For all the examined samples broad EPR lines (deltaBpp: 0.48-0.68 mT) with g-factors of 2.0045-2.0060 characteristic for o-semiquinone free radicals were observed. Free radicals concentrations (N) in the tested samples, g-factors, amplitudes (A), integral intensities (I) and linewidths (deltaBpp) of the EPR spectra, were analyzed. The EPR lines were homogeneously broadened. Continuous microwave saturation of the EPR spectra indicated that slow spin-lattice relaxation processes existed in all the tested melanin samples. The relatively slowest spin-lattice relaxation processes characterized melanin isolated from A-375 cells treated with both VPA and CPT. The changes of the EPR spectra with increasing microwave power in the range of 2.2-70 mW were evaluated. Free radicals concentrations in the melanin from A-375 cells were higher than in the synthetic DOPA-melanin. The strong increase of free radicals concentration in the melanin from A-375 cells was observed after their treating by VPA. CPT also caused the increase of free radicals concentrations in the examined natural melanin. The free radicals concentration in melanin isolated from A-375 cells treated with both VPA and CPT was slightly higher than those in melanin from the control cells.

Comparison of dissolution profiles of theophylline extended-release dosage forms.

Dissolution testing is a very important tool used to demonstrate the similarity between different formulations. Due to a narrow therapeutic range of theophylline, it is crucial to investigate the differences in the rate of release of this drug between the products. The aim of study was to compare the dissolution profiles of theophylline extended-release dosage forms available on Polish market: Theoplus, Theovent, Theospirex retard, and Euphyllin long. The investigation of theophylline release from tablets was performed by the basket apparatus type DT700 (Erweka). The difference and similarity factor was used to compare the obtained dissolution profiles. The obtained values showed that dissolution profiles of investigated formulations were not equivalent to each other. The tablets differed by the mechanism of drug release also.

Valproic acid enhances cisplatin cytotoxicity in melanoma cells.

In recent years, there has been a growing interest in anticancer potential of valproic acid (VPA) resulting from inhibition of histone deacetylase activity. The aim of our study was to evaluate the influence of valproic acid and cisplatin (CPT) on the growth rate of human melanoma cell lines: A375 (melanotic) and C32 (amelanotic). Both tested drugs decreased cell proliferation in a dose-dependent manner. VPA used alone significantly inhibited the growth of both cell lines at concentrations of 3 and 10 mM. Cisplatin significantly decreased cell proliferation at concentration = 0.3 microM. However, VPA enhanced the cytostatic action of CPT since simultaneous exposure of cells to 1 mM VPA and 0.1 microM CPT resulted in a significant reduction of cell growth. It can be concluded that VPA increases the sensitivity of melanoma cells to chemotherapeutic agent -- cisplatin.

Effects of 300 mT static magnetic field on IL-6 secretion in normal human colon myofibroblasts.

Intestinal subepithelial myofibroblasts play crucial role in the growth and development of the intestine. Colitis, small bowel injury, gastric ulcer disease and inflammatory bowel disease (IBD) accompany the increase of number of activated myofibroblasts. In the last few years, the increasing production of electromagnetic (EMF) and static magnetic fields (SMF), due to the expanding use of electronic devices in everyday life, has led to a number of studies on the effects of these fields on living organisms. EMF therapy, because of its anti-inflammatory properties, may be used in medicine in IBD treatment. This mechanism has not been elucidated yet. In the present work normal human colon myofibroblasts CCD-18Co were exposed to SMF with a flux density of 300 mT. After 24 h incubation TNF-alpha-dependent IL-6 secretion was determined with ELISA kit (RandD Systems).The influence of magnetic field and its effect on cell proliferation were determined with TOX-2 (In Vitro Toxicology Assay Kit XTT Based, TOX-2, Sigma) and CyQUANT NF cell proliferation assay kit (Molecular Probes). It was shown that SMF inhibited TNF-alpha-dependent IL-6 secretion. The observed effects were statistically significant and depended on the time of incubation. Moreover, SMF triggered cell proliferation whereas it did not alter cell viability. IL-6 belongs to pro-inflammatory cytokines family and plays a crucial role in IBD. Inhibition of IL-6 secretion by SMF and lack of its cytotoxic effect seem to be advantageous whilst SMF is implicated in the treatment of inflammatory diseases associated by increase in number of activated myofibroblasts.

Chemical composition of Desulfovibrio desulfuricans lipid A.

Lipopolysaccharides also called endotoxins are an integral component of the outer membrane of Gram-negative bacteria. When released from the bacterial surface, they interact with a host immune system, triggering excessive inflammatory response. Lipid A is the biologically most active part of endotoxin, and its activity is modulated by the quantity, quality and arrangement of its fatty acids. Desulfovibrio desulfuricans is sulfate-reducing, Gram-negative bacterium that is supposed to be opportunistic pathogens of humans and animals. In the present study, chemical composition of lipid A from various strains of D. desulfuricans was analyzed by gas chromatography/mass spectrometry. It was found that the fatty acid component of the lipid A contains dodecanoic, tetradecanoic, 3-hydroxytetradecanoic and hexadecanoic acids, and its carbohydrate core is composed of glucosamine. The analysis of 3-acyloxyacyl residue of the lipid A revealed the presence of amide-bound 3-(dodecanoyloxy)tetradecanoic and 3-(hexadecanoyloxy)tetradecanoic acids and ester-bound 3-(tetradecanoyloxy)tetradecanoic acid. It was concluded that both fatty acid and 3-acyloxyacyl residue profiles of the lipid A from the studied bacteria were similar to those of E. coli and S.enterica.