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1
Wang, Cindy, Engy A. Mahrous, Richard E. Lee, Martha M. Vestling, and Kuni Takayama. "Novel Polyoxyethylene-Containing Glycolipids Are Synthesized inCorynebacterium matruchotiiandMycobacterium smegmatisCultured in the Presence of Tween 80." Journal of Lipids 2011 (2011): 1–12. http://dx.doi.org/10.1155/2011/676535.
Анотація:
The addition of polyoxyethylene sorbitan monooleate (Tween 80) to a culture of mycobacteria greatly influences cell permeability and sensitivity to antibiotics but very little is known regarding the underlying mechanism. Here we show thatCorynebacterium matruchotii(surrogate of mycobacteria) converts Tween 80 to a structural series of polyoxyethylenic acids which are then used to form novel series-2A and series-2B glycolipids. Minor series-3 glycolipids were also synthesized. The polyoxyethylenic acids replaced corynomycolic acids in the cell wall. Correspondingly the trehalose dicorynomycolate content was reduced. MALDI mass spectrometry, MS-MS,1H-NMR, and13C-NMR were used to characterize the series-2 glycolipids. Series-2A glycolipid is trehalose 6-C36:2-corynomycolate-6′-polyoxyethylenate and series-2B glycolipid is trehalose 6-C36:2-corynomycolate-6′-furan ring-containing polyoxyethylenate.Mycobacterium smegmatisgrown in the presence of Tween 80 also synthesizes series-2 type glycolipids. The synthesis of these novel glycolipids in corynebacteria and mycobacteria should result in gross changes in the cell wall permeability and drug sensitivity.
2
Symington, F. W., D. L. Hedges, and S. Hakomori. "Glycolipid antigens of human polymorphonuclear neutrophils and the inducible HL-60 myeloid leukemia line." Journal of Immunology 134, no. 4 (April 1, 1985): 2498–506. http://dx.doi.org/10.4049/jimmunol.134.4.2498.
Анотація:
Abstract Glycolipid and cell surface carbohydrate antigens of human polymorphonuclear neutrophils (PMN) and of HL-60 myeloid leukemia cells were analyzed with a panel of defined, monoclonal anti-carbohydrate antibodies. Antigenicities of intact PMN, HL-60, and retinoic acid-induced HL-60 (r.a.-HL-60) were studied by flow cytofluorometry. These three cell populations displayed quantitative differences, some of which were induction dependent, in their expression of lactosyl, N-acetyllactosaminyl, Y-hapten (Fuc alpha 1----2Gal beta 1----4(Fuc alpha 1----3)GlcNAc beta 1----R), and sialosyl-X-hapten (SA alpha 2----3Gal beta 1----4(Fuc alpha 1----3)GlcNAc beta 1----R) specificities. Structures reactive with antibodies specific for long-chain mono-, and di- or tri- alpha 1----3 fucosylated lacto-series glycolipids were also detected. Glycosphingolipids purified from organic extracts of these cells were analyzed to seek information concerning the chemical basis for these surface antigenic differences, to assess the structural and antigenic diversity of PMN and HL-60 glycolipids, and to quantitate chemically and antigenically prominent glycolipids. Binding of monoclonal antibodies to thin-layer chromatograms demonstrated that each of the specificities on intact cells was carried by one or more distinct glycolipids. The abundance of immunoreactive glycolipids in the extracts paralleled the relative staining intensities of the intact cell populations. Several "cryptic" glycolipid antigens, including alpha 2----6 sialosylated structures enriched five- to 10-fold in PMN extracts, were not detected on intact cells. Lactosylceramide accounted for two-thirds of the approximately 1.5 X 10(9) glycolipid molecules contained in each PMN. The remaining glycolipid antigens appeared to include structurally diverse fucolipids, fucogangliosides, and neutral and sialosylated glycolipids with Gal beta 1----4GlcNAc beta 1----R terminal core structure. The abundance, diversity, and induction-dependent expression of these structures suggest that they may participate in PMN maturation and function.
3
Sandhoff, Konrad, and Thomas Kolter. "Biosynthesis and degradation of mammalian glycosphingolipids." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 358, no. 1433 (May 29, 2003): 847–61. http://dx.doi.org/10.1098/rstb.2003.1265.
Анотація:
Glycolipids are a large and heterogeneous family of sphingolipids that form complex patterns on eukaryotic cell surfaces. This molecular diversity is generated by only a few enzymes and is a paradigm of naturally occurring combinatorial synthesis. We report on the biosynthetic principles leading to this large molecular diversity and focus on sialic acid–containing glycolipids of the ganglio–series. These glycolipids are particularly concentrated in the plasma membrane of neuronal cells. Their de novo synthesis starts with the formation of the membrane anchor, ceramide, at the endoplasmic reticulum (ER) and is continued by glycosyltransferases of the Golgi complex. Recent findings from genetically engineered mice are discussed. The constitutive degradation of glycosphingolipids (GSLs) occurs in the acidic compartments, the endosomes and the lysosomes. Here, water–soluble glycosidases sequentially cleave off the terminal carbohydrate residues from glycolipids. For glycolipid substrates with short oligosaccharide chains, the additional presence of membrane–active sphingolipid activator proteins (SAPs) is required. A considerable part of our current knowledge about glycolipid degradation is derived from a class of human diseases, the sphingolipidoses, which are caused by inherited defects within this pathway. A new post–translational modification is the attachment of glycolipids to proteins of the human skin.
4
Cheng, Janice M. H., Ashna A. Khan, Mattie S. M. Timmer, and Bridget L. Stocker. "Endogenous and Exogenous CD1-Binding Glycolipids." International Journal of Carbohydrate Chemistry 2011 (April 5, 2011): 1–13. http://dx.doi.org/10.1155/2011/749591.
Анотація:
In the same way that peptide antigens are presented by major histocompatibility complex (MHC) molecules, glycolipid antigens can also activate the immune response via binding to CD1 proteins on antigen-presenting cells (APCs) and stimulate CD1-restricted T cells. In humans, there are five members of the CD1 family, termed CD1a–e, of which CD1a–d are involved in glycolipid presentation at the cell surface, while CD1e is involved in the intracellular trafficking of glycolipid antigens. Both endogenous (self-derived) and exogenous (non-self-derived) glycolipids have been shown to bind to members of the CD1 family with varying degrees of specificity. In this paper we focus on the key glycolipids that bind to the different members of the CD1 family.
5
Godavarthy, Padmavathi, and Y. Sunila Kumari. "Glycolipids as Potential Energy Molecules during Starvation in Climbing Perch,Anabas testudineus(Bloch)." International Journal of Zoology 2014 (2014): 1–5. http://dx.doi.org/10.1155/2014/476798.
Анотація:
Glycolipids are membrane lipids which act as cellular markers and also provide energy for the cells. The present study is an attempt to understand whether glycolipids can act as energy sources during fasting. To achieve this, we selected and subjectedAnabas testudineusto short-term (15 days) and long-term (60 days) laboratory starvation. We estimated glycolipids biochemically using a standard protocol in six different tissues. Results showed a selective decline in glycolipid concentration in certain tissues, and also an increase was observed in some tissues. Short-term fasting led to a decline in glycolipids in tissues such as brain (P<0.05), accessory respiratory organ (P<0.001), pectoral and lateral line muscle. Liver and kidney (P<0.002) reported an increase. Long term starvation also resulted in a decline in tissues such as liver (P<0.001), kidney (P<0.001), brain, and accessory respiratory organ. Muscle tissue,that is, both the pectoral (P<0.002) and lateral line muscle (P<0.05), showed an increase in the glycolipid fraction. This selective decline in glycolipid content of certain tissues suggests a possible utilization of these lipids during starvation and the significant upsurge observed in certain tissues suggests a simultaneous synthesis occurring along the degradation, probably reducing the oxidative stress created by ROS (reactive oxygen species).
6
Colmenares, M., M. Tiemeyer, P. Kima, and D. McMahon-Pratt. "Biochemical and Biological Characterization of the Protective Leishmania pifanoi Amastigote Antigen P-8." Infection and Immunity 69, no. 11 (November 1, 2001): 6776–84. http://dx.doi.org/10.1128/iai.69.11.6776-6784.2001.
Анотація:
ABSTRACT The Leishmania pifanoi amastigote antigen P-8 has been previously shown to induce protective immunity in a murine model of cutaneous leishmaniasis (L. Soong, S. M. Duboise, P. Kima, and D. McMahon-Pratt, Infect. Immun. 63:3559–3566, 1995). As this antigen is of interest for further vaccine studies, the biochemical characterization of P-8 was undertaken. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western-blot analysis, and gel filtration chromatography revealed that P-8 antigen consisted of two proteoglycolipid complexes. The P-8 epitope is associated with theL. pifanoi amastigote-specific glycolipid components found in the two complexes. The P-8 complex 1 (P-8c1) consists of a 56-kDa serine metalloproteinase, apolipoprotein E (derived from fetal bovine serum), and amastigote-specific glycolipids. The P-8 complex 2 (P-8c2) consists of a 31-kDa cysteine proteinase associated with amastigote glycolipids. Biochemical analyses suggest that the P-8 antigenic glycolipids may be distinct from previously describedLeishmania glycolipids (glycosylinositolphospholipids and sphingoglycolipids). Protective immunity studies revealed that P-8c1 (serine metalloproteinase-glycolipid complex) confers comparable protection against infection as immunopurified P-8. The isolated P-8c2 (cysteine proteinase-glycolipid complex) does not provide significant protection, nor does stimulation with P-8c2 result in significant T-cell activation in P-8- or P-8c2-vaccinated mice. Consequently, the P-8c1 complex appears to be the immunodominant component of P-8.
7
Künemund, V., F. B. Jungalwala, G. Fischer, D. K. Chou, G. Keilhauer, and M. Schachner. "The L2/HNK-1 carbohydrate of neural cell adhesion molecules is involved in cell interactions." Journal of Cell Biology 106, no. 1 (January 1, 1988): 213–23. http://dx.doi.org/10.1083/jcb.106.1.213.
Анотація:
We investigated whether the L2/HNK-1 carbohydrate epitope, expressed by two unusual glycolipids and several neural adhesion molecules, including L1, neural cell adhesion molecule, J1, and the myelin-associated glycoprotein, is involved in adhesion. Monoclonal L2 antibodies, the L2/HNK-1-reactive, sulfate-3-glucuronyl residue carrying glycolipids (L2 glycolipid) and a tetrasaccharide derived from the L2 glycolipid (L2 tetrasaccharide) were added to microexplant cultures of early postnatal mouse cerebellum, and cell migration and process extension were monitored. On the substrate poly-D-lysine, Fab fragments of L2 antibodies, L2 glycolipid, and L2 tetrasaccharide inhibited outgrowth of astrocytic processes and migration of cell bodies, but only L2 glycolipid and L2 tetrasaccharide reduced neurite outgrowth. On laminin, L2 antibodies, L2 glycolipid, and L2 tetrasaccharide inhibited outgrowth of astrocytic processes. Additionally, L2 glycolipid and L2 tetrasaccharide inhibited cell migration and neurite outgrowth. Several negatively charged glycolipids, lipids, and saccharides were tested for control and found to have no effect on outgrowth patterns, except for sulfatide and heparin, which modified outgrowth patterns in a similar fashion as L2 glycolipid and L2 tetrasaccharide. On astrocytes none of the tested compounds interfered with explant outgrowth. In short-term adhesion assays L2 glycolipid, sulfatide, and heparin inhibited adhesion of neural cells to laminin. L2 glycolipid and sulfatide interfered with neuron to astrocyte and astrocyte to astrocyte adhesion, but not with neuron-neuron adhesion. The most straightforward interpretation of these observations is that the L2/HNK-1 carbohydrate and the sulfated carbohydrates, sulfatide and heparin, act as ligands in cell adhesion.
8
WUHRER, Manfred, Sandra RICKHOFF, Roger D. DENNIS, Günter LOCHNIT, Peter T. SOBOSLAY, Stefan BAUMEISTER, and Rudolf GEYER. "Phosphocholine-containing, zwitterionic glycosphingolipids of adult Onchocerca volvulus as highly conserved antigenic structures of parasitic nematodes." Biochemical Journal 348, no. 2 (May 23, 2000): 417–23. http://dx.doi.org/10.1042/bj3480417.
Анотація:
Human Onchocerca volvulus infection sera were found to recognize zwitterionic glycolipids of O. volvulus and to cross-react with those of other parasitic nematodes (Ascaris suum, Setaria digitata and Litomosoides sigmodontis). By the use of an epitope-specific monoclonal antibody, zwitterionic glycolipids of all these nematode species were observed to contain the antigenic determinant phosphocholine. A hyperimmune serum specific for arthro-series glycolipid structures reacted with the various neutral glycolipids of all these nematodes, which demonstrated that their oligosaccharide moieties belonged to the arthro-series of protostomial glycolipids. These results indicated that arthro-series glycosphingolipids carrying, in part, phosphocholine substituents, represent highly conserved, antigenic glycolipid markers of parasitic nematodes. Three glycolipid components of the O. volvulus zwitterionic fraction were structurally characterized by matrix-assisted laser-desorption/ionization time-of-flight MS, methylation analysis and exoglycosidase treatment. Their chemical structures were elucidated to be phosphocholine-6GlcNAc(β1-3)Man(β1-4)Glc(1-1)ceramide, GalNAc(β1-4)[phosphocholine-6]GlcNAc(β1-3)Man(β1-4)Glc(1-1)ceramide and Gal(α1-3)GalNAc(β1-4)[phosphocholine-6]GlcNAc(β1-3)Man(β1-4)Glc(1-1)ceramide for the zwitterionic ceramide tri-, tetra- and penta-hexosides respectively. The ceramide composition was found to be dominated by 2-hydroxylated docosanoic (C22h:0), tricosanoic (C23h:0) and tetracosanoic (C24h:0) acids, and C17 sphingosine (Cd17:1) (where h is hydroxylated and d is dihydroxylated).
9
Anisuzzaman, Md, Feng Jin, Kamrunnahar Kabery, U.-Cheol Jeong, Hyun-Chol Jung, Sang-Ro Lee, and Seok-Joong Kang. "Lipid Class and Fatty Acid Compositions of Dried Sea Cucumber Apostichopus japonicus." Open Food Science Journal 11, no. 1 (July 31, 2019): 79–86. http://dx.doi.org/10.2174/1874256401911010079.
Анотація:
Introduction: Sea cucumber, Apostichopus japonicus, is becoming popular around the world due to its nutritional and medicinal properties. There are still no detailed chemical studies of the lipid class, glycolipids compositions of sea cucumber. Methods: This study was conducted to determine the lipid class and glycolipid compositions of dried sea cucumber, A. japonicus, and analyze fatty acid compositions of Monogalactosyl Diglycerides (MGDG), Steryl Glycosides (SG) and Sulfoquinovosyl Diglycerides (SQDG). Total lipids of sea cucumber were extracted by Bligh and Dyer method and Sep-Pak Silica plus long cartridge, and Thin Layer Chromatography (TLC) silica gel G-60 F254 was used for the separation of different lipid classes and glycolipid compositions. The composition of fatty acids was analyzed by GC. Results & Conclusion: The level of total lipids in the dried sea cucumber, Apostichopus japonicus, was 4 ± 1% of dry weight (w/w) and the amount of neutral lipids, glycolipids and phospholipids was 31 ± 1%, 29 ± 1% and 40 ± 1% of the total lipids (w/w), respectively. MGDG, SG and SQDG were the major glycolipids, and the contents were 37.5 ± 0.3%, 33.8 ± 0.5% and 23.6 ± 0.7% of the total glycolipids (w/w), respectively and significantly higher than other glycolipids (p < 0.05). SQDG contained much higher Arachidonic Acid (AA), Eicosapentaenoic Acid (EPA) and MGDG contained higher Docosahexaenoic Acid (DHA) compared with SG (p < 0.05). Further investigation is required to understand the positional distribution of fatty acids and molecular species in MGDG, SG and SQDG in detail.
10
De Libero, Gennaro, and Lucia Mori. "Self Glycosphingolipids: New Antigens Recognized by Autoreactive T Lymphocytes." Physiology 18, no. 2 (April 2003): 71–76. http://dx.doi.org/10.1152/nips.01418.2002.
Анотація:
T cells may recognize glycolipids and lipids of bacterial and self origin associated with the CD1 antigen-presenting molecules. Understanding the mechanisms governing CD1-self glycolipid interaction will provide information on the molecular rules of glycolipid presentation and suggest new approaches to immunotherapy.
11
Alon, R., T. Feizi, C. T. Yuen, R. C. Fuhlbrigge, and T. A. Springer. "Glycolipid ligands for selectins support leukocyte tethering and rolling under physiologic flow conditions." Journal of Immunology 154, no. 10 (May 15, 1995): 5356–66. http://dx.doi.org/10.4049/jimmunol.154.10.5356.
Анотація:
Abstract Selectin interactions with glycolipids have been examined previously under static conditions, whereas physiologic interactions mediated by selectins take place under flow. We find that under physiologic flow conditions, sialyl Lewis(x) (sLe(x)) glycolipid and sialyl Lewisa (sLe(a)) neoglycolipid support tethering and rolling adhesions of Chinese hamster ovary (CHO) cells expressing E-selectin and lymphoid and myeloid cells expressing L-selectin. These selectin-mediated adhesions persist at the highest shear stresses that occur in postcapillary venules in vivo and occur at lower site densities than found for sLe(x) on neutrophils. The interactions are Ca(2+)-dependent and can be specifically and completely blocked with anti-selectin mAbs. Asialo nonfucosylated glycolipids are inactive, and sulfatide supports weak tethering, but not rolling, of L-selectin-expressing cells. Rolling velocities and resistance to detachment are related to the glycolipid site density and fall within the range measured for neutrophil and myeloid cell rolling on substrates containing purified selectins. These observations are the first indication that glycolipids can interact with selectins in physiologic flow conditions, and can contribute to rolling adhesions.
12
Itonori, S., T. Shirai, Y. Kiso, Y. Ohashi, K. Shiota, and T. Ogawa. "Glycosphingolipid composition of rat placenta: changes associated with stage of pregnancy." Biochemical Journal 307, no. 2 (April 15, 1995): 399–405. http://dx.doi.org/10.1042/bj3070399.
Анотація:
The composition of glycolipids and their changes in the placenta were investigated in the normal pregnant rat. Total lipid fractions extracted from the placenta between days 12 and 20 of pregnancy (day 0 = oestrus) were subjected to glycolipid analysis using DEAE-Sephadex chromatography, silica-gel HPLC, silica-gel TLC, TLC/immunostaining, matrix-assisted secondary-ion mass spectrometry in the negative-ion mode and 1H NMR. Glycolipids identified in the rat placenta were: gangliosides GM3 (NeuAcLacCer and NeuGcLacCer) and GD3 (NeuAcNeuAcLacCer, NeuAcNeuGcLacCer and NeuGcNeuAcLacCer), and neutral glycolipids ceramide monosaccharide (CMH) (GlcCer), ceramide disaccharide (CDH) (LacCer), ceramide trisaccharide (CTH) (Gb3Cer) and ceramide tetrasaccharide (CQH) (Gb4Cer). The content of neutral glycolipids was higher than that of gangliosides throughout pregnancy. Of the neutral glycolipids, CMH and CTH predominated and the level of CDH was low at mid-pregnancy. During late pregnancy, CMH and CTH decreased and CDH increased markedly. CQH remained at a low level throughout pregnancy. Of the gangliosides, GM3 was predominant on days 12-16 and then decreased, whereas GD3, which was low on day 12, increased slightly on day 16 and maintained the same level thereafter. Immunohistochemical studies indicated that these changes in the expression of major gangliosides from GM3 to GD3 occurred in labyrinthine trophoblasts. Thus expression of these glycolipids appears to change markedly during pregnancy.
13
Fredman, P., L. Mattsson, K. Andersson, P. Davidsson, I. Ishizuka, S. Jeansson, J. E. Månsson, and L. Svennerholm. "Characterization of the binding epitope of a monoclonal antibody to sulphatide." Biochemical Journal 251, no. 1 (April 1, 1988): 17–22. http://dx.doi.org/10.1042/bj2510017.
Анотація:
An IgG1 monoclonal antibody, Sulph I, reacting with sulphatide (3′-sulphogalactosylceramide), was produced by immunizing Balb/c mice with that glycolipid coated on Salmonella minnesota bacterial membrane. Radioimmunodetection of the binding of the monoclonal antibody to structurally related glycolipids adsorbed to microtitre plates or chromatographed on thin-layer plates was used to determine its binding epitope. The antibody showed similar binding avidity to three sulphated glycolipids: sulphatide, sulpholactosylceramide and seminolipid. Lysosulphatide did bind the antibody, but, compared with sulphatide, 30 times more antigen was needed for half-maximal binding. Bis(sulphogangliotriosyl)ceramide and bis-sulphogangliotetraosylceramide did not bind the antibody. These results suggest that terminal galactose-3-O-sulphate and part of the hydrophobic region of the glycolipid are recognized by the Sulph I antibody.
14
Galili, U., B. A. Macher, J. Buehler, and S. B. Shohet. "Human natural anti-alpha-galactosyl IgG. II. The specific recognition of alpha (1----3)-linked galactose residues." Journal of Experimental Medicine 162, no. 2 (August 1, 1985): 573–82. http://dx.doi.org/10.1084/jem.162.2.573.
Анотація:
A natural IgG antibody (anti-Gal) with alpha-galactosyl binding specificity has been found in large amounts (0.5 - 1.0% of serum IgG) in all individuals tested. It has been purified by affinity chromatography on a column of melibiose-Sepharose. In addition to its affinity for normal and pathological senescent human red cells, the antibody readily interacts with rabbit red blood cell (RRBC) glycolipids with alpha-galactosyl terminal residues. Two types (glycosidic linkages of 1----3 vs. 1----4) of rabbit red cells glycolipids with terminal alpha-galactosyl residues were tested for antibody binding. The antibody specifically bound to glycolipids with Gal alpha 1----3 terminal residues, and treatment of these glycolipids with alpha-galactosidase abolished binding. Hemagglutination inhibition studies with oligosaccharides of known structure also showed that the antibody binds specifically to glycoconjugates with an alpha 1----3 terminal galactose residue. Anti-Gal did not bind to a human B-active glycolipid, indicating that fucose-linked alpha 1----2 to the penultimate galactose prevents anti-Gal binding. The anti-Gal specificity for RRBC glycolipids also paralleled that of the alpha-galactosyl-specific Bandeiraea simplicifolia lectin. The possible reasons for the occurrence of this unique antibody in human serum are discussed.
15
Arino, S., R. Marchal, and J. P. Vandecasteele. "Production of new extracellular glycolipids by a strain ofCellulomonas cellulans(Oerskovia xanthineolytica) and their structural characterization." Canadian Journal of Microbiology 44, no. 3 (March 1, 1998): 238–43. http://dx.doi.org/10.1139/w97-156.
Анотація:
Glycolipid-producing bacteria were isolated from soil samples. One of the strains, identified as Cellulomonas cellulans (Oerskovia xanthineolytica), was found to produce significant amounts of unusual extracellular glycolipids, which were shown to be composed of at least 11 individual compounds. Hydrolysis of the glycolipid mixture and gas chromatography - mass spectrometry analysis revealed the presence of fatty acids and hydroxy fatty acids ranging from C10to C18, 16 of which were identified. The glycidic moiety consisted of glucose, rhamnose, and ribose. The same sugars were found to be present in the cell wall of Cellulomonas cellulans, which also contained polar lipids including glycolipids. During strain cultivation, glycolipid excretion was stimulated when nitrogen was exhausted from the culture medium. In these conditions, the production in fermenters on glycerol, expressed in glucose equivalents, reached 8.9 g/L. Cell hydrophobicity, which rose to 95% during the growth phase, decreased to 50% during the production phase. The overall results show that the bacterial cell wall is involved in the synthesis of these new extracellular glycolipids.Key words: glycolipid, excretion, Cellulomonas cellulans, Oerskovia xanthineolytica, cell wall.
16
Shu, Qin, Hanghang Lou, Tianyu Wei, Xiayu Liu, and Qihe Chen. "Contributions of Glycolipid Biosurfactants and Glycolipid-Modified Materials to Antimicrobial Strategy: A Review." Pharmaceutics 13, no. 2 (February 6, 2021): 227. http://dx.doi.org/10.3390/pharmaceutics13020227.
Анотація:
Glycolipid biosurfactants are natural amphiphiles and have gained particular interest recently in their biodegradability, diversity, and bioactivity. Microbial infection has caused severe morbidity and mortality and threatened public health security worldwide. Glycolipids have played an important role in combating many diseases as therapeutic agents depending on the self-assembly property, the anticancer and anti-inflammatory properties, and the antimicrobial properties, including antibacterial, antifungal, and antiviral effects. Besides, their role has been highlighted as scavengers in impeding the biofilm formation and rupturing mature biofilm, indicating their utility as suitable anti-adhesive coating agents for medical insertional materials leading to a reduction in vast hospital infections. Notably, glycolipids have been widely applied to the synthesis of novel antimicrobial materials due to their excellent amphipathicity, such as nanoparticles and liposomes. Accordingly, this review will provide various antimicrobial applications of glycolipids as functional ingredients in medical therapy.
17
Galili, Uri. "Conversion of Tumors into Autologous Vaccines by Intratumoral Injection ofα-Gal Glycolipids that Induce Anti-Gal/α-Gal Epitope Interaction". Clinical and Developmental Immunology 2011 (2011): 1–10. http://dx.doi.org/10.1155/2011/134020.
Анотація:
Anti-Gal is the most abundant antibody in humans, constituting 1% of immunoglobulins. Anti-Gal binds specificallyα-gal epitopes (Galα1-3Galβ1-4GlcNAc-R). Immunogenicity of autologous tumor associated antigens (TAA) is greatly increased by manipulating tumor cells to expressα-gal epitopes and bind anti-Gal. Glycolipids withαgal epitopes (α-gal glycolipids) injected into tumors insert into the tumor cell membrane. Anti-Gal binding to the multiple α-gal epitopesde novopresented on the tumor cells results in targeting of these cells to APC via the interaction between the Fc portion of the bound anti-Gal and Fcγ; receptors on APC. The APC process and present immunogenic TAA peptides and thus, effectively activate tumor specific CD4+ helper T cells and CD8+ cytotoxic T cells which destroy tumor cells in micrometastases. The induced immune response is potent enough to overcome immunosuppression by Treg cells. A phase I clinical trial indicated thatα-gal glycolipid treatment has no adverse effects. In addition to achieving destruction of micrometastases in cancer patients with advance disease,α-gal glycolipid treatment may be effective as neo-adjuvant immunotherapy. Injection ofα-gal glycolipids into primary tumors few weeks prior to resection can induce a protective immune response capable of destroying micrometastases expressing autologous TAA, long after primary tumor resection.
18
Laffoon, J., C. Lesch, and C. A. Squier. "A transmission electron microscopic study of porcine stratum corneum treated with topical applications of glycolipid." Proceedings, annual meeting, Electron Microscopy Society of America 44 (August 1986): 266–67. http://dx.doi.org/10.1017/s0424820100142955.
Анотація:
The mammalian epidermis forms a differentiated surface layer termed the stratum corneum (sc) which represents the principal barrier. It is now known that the permeability barrier is located in the intercellular region of the sc and consists largely of neutral lipids derived from glycolipids that are aligned to form a highly hydrophobic structure. It is possible that this barrier might be augmented by topical application of pure glycolipid, which could diffuse through the regions between the squarnes. We have examined this possibility by treating the backskin of pigs with glycolipids and then preparing the tissue for examination with the transmission electron microscope (TEM).
19
Julián, Esther, Lurdes Matas, José Alcaide, and Marina Luquin. "Comparison of Antibody Responses to a Potential Combination of Specific Glycolipids and Proteins for Test Sensitivity Improvement in Tuberculosis Serodiagnosis." Clinical Diagnostic Laboratory Immunology 11, no. 1 (January 2004): 70–76. http://dx.doi.org/10.1128/cdli.11.1.70-76.2004.
Анотація:
ABSTRACT The humoral response to different proteinaceous antigens of Mycobacterium tuberculosis is heterogeneous among patients with active disease, and this has originated in the proposal to use a combination of several specific antigens to find an efficient serodiagnostic test for tuberculosis (TB). However, to date, comparisons of antibody responses to several antigens in the same population have been carried out without consideration of antigenic cell wall glycolipids. In the present study the presence of immunoglobulin G (IgG), IgM, and IgA antibodies to M. tuberculosis glycolipids (sulfolipid I, diacyltrehaloses, triacyltrehaloses, and cord factor) was compared with the response to four commercially available tests based on the 38-kDa protein mixed with the 16-kDa protein or lipoarabinomannan. Fifty-two serum samples from TB patients and 83 serum samples from control individuals (48 healthy individuals and 35 non-TB pneumonia patients) were studied. Three relevant results were obtained. (i) Smear-negative TB patients presented low humoral responses, but the sera which did react principally showed IgA antibodies to some glycolipidic antigens. (ii) TB patients exhibit heterogeneous humoral responses against glycolipidic antigens. (iii) Finally, test sensitivity is improved (from 23 to 62%) when IgG and IgA antibodies are detected together in tests based on different antigens (proteins and glycolipids). We conclude that it is possible to include glycolipidic antigens in a cocktail of specific antigens from M. tuberculosis to develop a serodiagnostic test.
20
Dennis, R. D., S. Baumeister, C. Smuda, C. Lochnit, T. Waider, and E. Geyer. "Initiation of chemical studies on the immunoreactive glycolipids of adult Ascaris suum." Parasitology 110, no. 5 (June 1995): 611–23. http://dx.doi.org/10.1017/s0031182000065331.
Анотація:
SUMMARYThere is a general lack of basic information concerning one class of glycoconjugate, the glycolipids, from parasitic nematodes. As the prototype, the neutral glycolipid fraction derived from adult males of Ascaris suum was investigated as to its chromatographic, differential chemical staining, antigenic and chemical properties. The thin-layer chromato-graphy-resolved neutral fraction glycolipids could be classified into components of fast and slow migrating band groups. Immunoreactivity was restricted to the latter as detected by IgG and IgM anti-neutral fraction glycolipid antibody levels in serial infection sera of mice. Similarities of chromatography, antigenicity and serological cross-reactivity have been extended to the neutral glycolipid fractions of other parasitic nematodes: Litomosoides carinii and Nippostrongylus brasiliensis. Chemical, differential chemical staining and enzymatic analyses identified the Ascaris suum antigenic, slow migrating band group of components as amphoteric glycosphingolipids, and not the originally hypothesized glyco-glycerolipids or glycosylphosphatidylinositols, that contained typical neutral monosaccharide constituents and a zwitter-ionic phosphodiester linkage, most probably phosphocholine. Glycosphingolipid-immunoreactivity is eliminated on cleavage of the zwitterionic phosphodiester linkage by hydrofluoric acid treatment.
21
Hove, Petronella R., Forgivemore Magunda, Maria Angela de Mello Marques, M. Nurul Islam, Marisa R. Harton, Mary Jackson, and John T. Belisle. "Identification and functional analysis of a galactosyltransferase capable of cholesterol glycolipid formation in the Lyme disease spirochete Borrelia burgdorferi." PLOS ONE 16, no. 6 (June 1, 2021): e0252214. http://dx.doi.org/10.1371/journal.pone.0252214.
Анотація:
Borrelia burgdorferi (Bb), the etiological agent of Lyme disease, produces a series of simple glycolipids where diacylglycerol and cholesterol serve as the precursor. The cholesterol-based glycolipids, cholesteryl 6-O-acyl-β-D-galactopyranoside (ACGal) and cholesteryl-β-D-galactopyranoside (CGal) are immunogenic and proposed to contribute to the pathogenesis of Lyme disease. Detailed studies of CGal and ACGal in Bb have been hampered by a lack of knowledge of their underlying biosynthetic processes. The genome of Bb encodes four putative glycosyltransferases, and only one of these, BB0572, was predicted to be an inverting family 2 glycosyltransferase (GT2 enzyme) capable of using UDP-galactose as a substrate and forming a β-glycosidic bond. Comparison of the 42 kDa BB0572 amino acid sequence from Bb with other Borrelia spp demonstrates that this protein is highly conserved. To establish BB0572 as the galactosyltransferase capable of cholesterol glycolipid formation in Bb, the protein was produced as a recombinant product in Escherichia coli and tested in a cell-free assay with 14C-cholesterol and UDP-galactose as the substrates. This experiment resulted in a radiolabeled lipid that migrated with the cholesterol glycolipid standard of CGal when evaluated by thin layer chromatography. Additionally, mutation in the predicted active site of BB0572 resulted in a recombinant protein that was unable to catalyze the formation of the cholesterol glycolipid. These data characterize BB0572 as a putative cholesterol galactosyltransferase. This provides the first step in understanding how Bb cholesterol glycolipids are formed and will allow investigations into their involvement in pathogen transmission and disease development.
22
Sun, Yafei, Qin Qin, Ke Song, Lijuan Sun, Tingting Jiang, Shiyan Yang, Zhouwen Li, Guohua Xu, Shubin Sun, and Yong Xue. "Does Sulfoquinovosyl Diacylglycerol Synthase OsSQD1 Affect the Composition of Lipids in Rice Phosphate-Deprived Root?" International Journal of Molecular Sciences 24, no. 1 (December 21, 2022): 114. http://dx.doi.org/10.3390/ijms24010114.
Анотація:
Lipids are the essential components of the cell intracellular and plasma membranes. Sulfoquinovosyldiacylglycerol (SQDG) is a glycolipid; glycolipids can replace phospholipids in maintaining phosphate (Pi) homeostasis in plants which are undergoing Pi starvation. Sulfoquinovosyl diacylglycerol synthase 1 (OsSQD1) is a critical enzyme in the first step of catalyzation in the formation of SQDG in rice. In this study, the expression pattern of different zones in roots of OsSQD1 in response to different Pi conditions is examined, and it is found that OsSQD1 is highly expressed in lateral roots under Pi-sufficient and -deficient conditions. The root phenotype observation of different OsSQD1 transgenic lines suggests that the knockout/down of OsSQD1 inhibits the formation and growth of lateral roots under different Pi conditions. Additionally, the lipid concentrations in OsSQD1 transgenic line roots indicate that OsSQD1 knockout/down decreases the concentration of phospholipids and glycolipids in Pi-starved roots. The OsSQD1 mutation also changes the composition of different lipid species with different acyl chain lengths, mainly under Pi-deprived conditions. The relative transcript expression of genes relating to glycolipid synthesis and phospholipid degradation is estimated to help study the mechanism by which OsSQD1 exerts an influence on the alteration of lipid composition and concentration in Pi-starved roots. Moreover, in Pi-starved roots, the knockout of OsSQD1 decreases the unsaturated fatty acid content of phospholipids and glycolipids. To summarize, the present study demonstrates that OsSQD1 plays a key role in the maintenance of phospholipid and glycolipid composition in Pi-deprived rice roots, which may influence root growth and development under Pi-deprived conditions.
23
Nimrichter, Leonardo, Monica M. Burdick, Kazuhiro Aoki, Wouter Laroy, Mark A. Fierro, Sherry A. Hudson, Christopher E. Von Seggern, et al. "E-selectin receptors on human leukocytes." Blood 112, no. 9 (November 1, 2008): 3744–52. http://dx.doi.org/10.1182/blood-2008-04-149641.
Анотація:
Selectins on activated vascular endothelium mediate inflammation by binding to complementary carbohydrates on circulating neutrophils. The human neutrophil receptor for E-selectin has not been established. We report here that sialylated glycosphingolipids with 5 N-acetyllactosamine (LacNAc, Galβ1-4GlcNAcβ1-3) repeats and 2 to 3 fucose residues are major functional E-selectin receptors on human neutrophils. Glycolipids were extracted from 1010 normal peripheral blood human neutrophils. Individual glycolipid species were resolved by chromatography, adsorbed as model membrane monolayers and selectin-mediated cell tethering and rolling under fluid shear was quantified as a function of glycolipid density. E-selectin–expressing cells tethered and rolled on selected glycolipids, whereas P-selectin–expressing cells failed to interact. Quantitatively minor terminally sialylated glycosphingolipids with 5 to 6 LacNAc repeats and 2 to 3 fucose residues were highly potent E-selectin receptors, constituting more than 60% of the E-selectin–binding activity in the extract. These glycolipids are expressed on human blood neutrophils at densities exceeding those required to support E-selectin–mediated tethering and rolling. Blocking glycosphingolipid biosynthesis in cultured human neutrophils diminished E-selectin, but not P-selectin, adhesion. The data support the conclusion that on human neutrophils the glycosphingolipid NeuAcα2-3Galβ1-4GlcNAcβ1-3[Galβ1-4(Fucα1-3)GlcNAcβ1-3]2[Galβ1-4GlcNAcβ1-3]2Galβ1-4GlcβCer (and closely related structures) are functional E-selectin receptors.
24
Warabi, Kaoru, William T. Zimmerman, Jingkai Shen, Annick Gauthier, Marilyn Robertson, B. Brett Finlay, Rob van Soest, and Raymond J. Andersen. "Pachymoside A A novel glycolipid isolated from the marine sponge Pachymatisma johnstonia." Canadian Journal of Chemistry 82, no. 2 (February 1, 2004): 102–12. http://dx.doi.org/10.1139/v03-183.
Анотація:
Crude extracts of the North Sea marine sponge Pachymatisma johnstonia showed promising activity in a new assay for inhibitors of bacterial type III secretion. Bioassay-guided fractionation resulted in the isolation of the pachymosides, a new family of sponge glycolipids. A major part of the structural diversity in this family of glycolipids involves increasing degrees of acetylation and differing positions of acetylation on a common pachymoside glycolipid template. All of the metabolites with these variations in acetylation pattern were converted into the same peracetylpachymoside methyl ester (2) for purification and spectroscopic analysis. Pachymoside A (1) is the component of the mixture that has natural acetylation at the eight galactose hydroxyls and at the C-6 hydroxyls of glucose-B and glucose-D. Chemical degradation and transformation in conjunction with extensive analysis of 800 MHz NMR data was used to elucidate the structure of pachymoside A (1). Key words: Pachymatisma johnstonia, marine sponge, pachymoside, glycolipid.
25
Leutou, Alain S., Jennifer R. McCall, Robert York, Rajeshwar R. Govindapur, and Andrea J. Bourdelais. "Anti-Inflammatory Activity of Glycolipids and a Polyunsaturated Fatty Acid Methyl Ester Isolated from the Marine Dinoflagellate Karenia mikimotoi." Marine Drugs 18, no. 3 (February 27, 2020): 138. http://dx.doi.org/10.3390/md18030138.
Анотація:
A new monogalactosyldiacylglycerol (MGDG), a known monogalactosylmonoacylglycerol (MGMG) and a known polyunsaturated fatty acid methyl ester (PUFAME) were isolated from the marine dinoflagellate Karenia mikimotoi. The planar structure of the glycolipids was elucidated using mass spectroscopy (MS) and nuclear magnetic resonance (NMR) analyses and comparisons to the known glycolipid to confirm its structure. The MGDG was characterized as 3-O-β-D-galactopyranosyl-1-O-3,6,9,12,15-octadecapentaenoyl-2-O-tetradecanoylglycerol 1. The MGMG and PUFAME were characterized as (2S)-3-O-β-D-galactopyranosyl-1-O-3,6,9,12,15-octadecapentaenoylglycerol 2 and Methyl (3Z,6Z,9Z,12Z,15Z)-octadeca-3,6,9,12,15-pentaenoate 3, respectively. The isolation of the PUFAME strongly supports the polyunsaturated fatty acid (PUFA) fragment of these glycolipids. The relative configuration of the sugar was deduced by comparisons of 3JHH values and proton chemical shifts with those of known glycolipids. All isolated compounds MGDG, MGMG and PUFAME 1-3 were evaluated for their antimicrobial and anti-inflammatory activity. All compounds modulated macrophage responses, with compound 3 exhibiting the greatest anti-inflammatory activity.
26
Chen, Yeng-Nan, Jung-Tung Hung, Fan-Dan Jan, Yung-Yu Su, Jih-Ru Hwu, Alice L. Yu, Avijit K. Adak та Chun-Cheng Lin. "Diversity-Oriented Synthesis of a Molecular Library of Immunomodulatory α-Galactosylceramides with Fluorous-Tag-Assisted Purification and Evaluation of Their Bioactivities in Regard to IL-2 Secretion". International Journal of Molecular Sciences 23, № 21 (2 листопада 2022): 13403. http://dx.doi.org/10.3390/ijms232113403.
Анотація:
Structural variants of α-galactosylceramide (α-GalCer) that stimulate invariant natural killer T (iNKT) cells constitute an emerging class of immunomodulatory agents in development for numerous biological applications. Variations in lipid chain length and/or fatty acids in these glycoceramides selectively trigger specific pro-inflammatory responses. Studies that would link a specific function to a structurally distinct α-GalCer rely heavily on the availability of homogeneous and pure materials. To address this need, we report herein a general route to the diversification of the ceramide portion of α-GalCer glycolipids. Our convergent synthesis commences from common building blocks and relies on the Julia–Kocienski olefination as a key step. A cleavable fluorous tag is introduced at the non-reducing end of the sugar that facilitates quick purification of products by standard fluorous solid-phase extraction. The strategy enabled the rapid generation of a focused library of 61 α-GalCer analogs by efficiently assembling various lipids and fatty acids. Furthermore, when compared against parent α-GalCer in murine cells, many of these glycolipid variants were found to have iNKT cell stimulating activity similar to or greater than KRN7000. ELISA assaying indicated that glycolipids carrying short fatty N-acyl chains (1fc and 1ga), an unsubstituted (1fh and 1fi) or CF3-substituted phenyl ring at the lipid tail, and a flexible, shorter fatty acyl chain with an aromatic ring (1ge, 1gf, and 1gg) strongly affected the activation of iNKT cells by the glycolipid-loaded antigen-presenting molecule, CD1d. This indicates that the method may benefit the design of structural modifications to potent iNKT cell-binding glycolipids.
27
Schapiro, Florencia B., Clifford Lingwood, Wendy Furuya, and Sergio Grinstein. "pH-independent retrograde targeting of glycolipids to the Golgi complex." American Journal of Physiology-Cell Physiology 274, no. 2 (February 1, 1998): C319—C332. http://dx.doi.org/10.1152/ajpcell.1998.274.2.c319.
Анотація:
A small fraction of the molecules internalized by endocytosis reaches the Golgi complex through a retrograde pathway that is poorly understood. In the present work, we used bacterial toxins to study the retrograde pathway in Vero cells. The recombinant B subunit of verotoxin 1B (VT1B) was labeled with fluorescein to monitor its progress within the cell by confocal microscopy. This toxin, which binds specifically to the glycolipid globotriaosyl ceramide, entered endosomes by both clathrin-dependent and -independent pathways, reaching the Golgi complex. Once internalized, the toxin-receptor complex did not recycle back to the plasma membrane. The kinetics of internalization and the subcellular distribution of VT1B were virtually identical to those of another glycolipid-binding toxin, the B subunit of cholera toxin (CTB). Retrograde transport of VT1B and CTB was unaffected by addition of weak bases in combination with concanamycin, a vacuolar-type ATPase inhibitor. Ratio imaging confirmed that these agents neutralized the luminal pH of the compartments where the toxin was located. Therefore, the retrograde transport of glycolipids differs from that of proteins like furin and TGN38, which require an acidic luminal pH. Additional experiments indicated that the glycolipid receptors of VT1B and CTB are internalized independently and not as part of lipid “rafts” and that internalization is cytochalasin insensitive. We conclude that glycolipids utilize a unique, pH-independent retrograde pathway to reach compartments of the secretory system and that assembly of F-actin is not required for this process.
28
Ariga, T., R. V. Tao, B. C. Lee, M. Yamawaki, H. Yoshino, N. J. Scarsdale, T. Kasama, Y. Kushi, and R. K. Yu. "Glycolipid composition of human cataractous lenses. Characterization of Lewisx glycolipids." Journal of Biological Chemistry 269, no. 4 (January 1994): 2667–75. http://dx.doi.org/10.1016/s0021-9258(17)41996-x.
29
Aspeslagh, Sandrine, Yali Li, Esther Yu, Tine Decruy, Katrien Van Beneden, Enrico Girardi, Nora Pauwels та ін. "Functional and structural characterization of potent Th1 biasing 6′-derivatised α-GalCer iNKT cell agonists, and their superior role in tumor protection. (156.4)". Journal of Immunology 186, № 1_Supplement (1 квітня 2011): 156.4. http://dx.doi.org/10.4049/jimmunol.186.supp.156.4.
Анотація:
Abstract Invariant natural killer T cells are known to have marked immunomodulatory capacity due to their ability to produce copious amounts of effector cytokines. In this study, we report the first crystal structures of a novel class of strong Th1 biasing structural analogues of α-galactosylceramide by addition of aromatic structures on the 6-OH position of galactose. They are characterized by marked Th1 polarized cytokine patterns that are highly conserved between mice and men, and marked tumour protection in vivo. The strength of the Th1 response correlates well with enhanced lipid binding to CD1d as a result of an induced fit mechanism that binds the aromatic substitution as a third anchor, in addition to the two lipid chains. This induced fit is in contrast to another Th1 biasing glycolipid, α-C-GalCer, whose CD1d binding follows a conventional key-lock principle. These findings highlight the previously unexploited flexibility of CD1d in accommodating galactose-modified glycolipids and broaden the range of glycolipids that can stimulate iNKT cells. We speculate that glycolipids can be designed that induce a similar fit, thereby leading to superior and more sustained iNKT cell responses in vivo.
30
Moriguchi, Kota, Yumina Nakamura, Ah-Mee Park, Fumitaka Sato, Motoi Kuwahara, Sundar Khadka, Seiichi Omura, Ijaz Ahmad, Susumu Kusunoki, and Ikuo Tsunoda. "Anti-Glycolipid Antibody Examination in Five EAE Models and Theiler’s Virus Model of Multiple Sclerosis: Detection of Anti-GM1, GM3, GM4, and Sulfatide Antibodies in Relapsing-Remitting EAE." International Journal of Molecular Sciences 24, no. 16 (August 18, 2023): 12937. http://dx.doi.org/10.3390/ijms241612937.
Анотація:
Anti-glycolipid antibodies have been reported to play pathogenic roles in peripheral inflammatory neuropathies, such as Guillain–Barré syndrome. On the other hand, the role in multiple sclerosis (MS), inflammatory demyelinating disease in the central nervous system (CNS), is largely unknown, although the presence of anti-glycolipid antibodies was reported to differ among MS patients with relapsing-remitting (RR), primary progressive (PP), and secondary progressive (SP) disease courses. We investigated whether the induction of anti-glycolipid antibodies could differ among experimental MS models with distinct clinical courses, depending on induction methods. Using three mouse strains, SJL/J, C57BL/6, and A.SW mice, we induced five distinct experimental autoimmune encephalomyelitis (EAE) models with myelin oligodendrocyte glycoprotein (MOG)35–55, MOG92–106, or myelin proteolipid protein (PLP)139–151, with or without an additional adjuvant curdlan injection. We also induced a viral model of MS, using Theiler’s murine encephalomyelitis virus (TMEV). Each MS model had an RR, SP, PP, hyperacute, or chronic clinical course. Using the sera from the MS models, we quantified antibodies against 11 glycolipids: GM1, GM2, GM3, GM4, GD3, galactocerebroside, GD1a, GD1b, GT1b, GQ1b, and sulfatide. Among the MS models, we detected significant increases in four anti-glycolipid antibodies, GM1, GM3, GM4, and sulfatide, in PLP139–151-induced EAE with an RR disease course. We also tested cellular immune responses to the glycolipids and found CD1d-independent lymphoproliferative responses only to sulfatide with decreased interleukin (IL)-10 production. Although these results implied that anti-glycolipid antibodies might play a role in remissions or relapses in RR-EAE, their functional roles need to be determined by mechanistic experiments, such as injections of monoclonal anti-glycolipid antibodies.
31
Hollenbach, Rebecca, Delphine Muller, André Delavault, and Christoph Syldatk. "Continuous Flow Glycolipid Synthesis Using a Packed Bed Reactor." Catalysts 12, no. 5 (May 18, 2022): 551. http://dx.doi.org/10.3390/catal12050551.
Анотація:
Glycolipids are a class of biodegradable biosurfactants that are non-toxic and based on renewables, making them a sustainable alternative to petrochemical surfactants. Enzymatic synthesis allows a tailor-made production of these versatile compounds using sugar and fatty acid building blocks with rationalized structures for targeted applications. Therefore, glycolipids can be comprehensively designed to outcompete conventional surfactants regarding their physicochemical properties. However, enzymatic glycolipid processes are struggling with both sugars and fatty acid solubilities in reaction media. Thus, continuous flow processes represent a powerful tool in designing efficient syntheses of sugar esters. In this study, a continuous enzymatic glycolipid production catalyzed by Novozyme 435® is presented as an unprecedented concept. A biphasic aqueous–organic system was investigated, allowing for the simultaneous solubilization of sugars and fatty acids. Owing to phase separation, the remaining non-acylated glucose was easily separated from the product stream and was refed to the reactor forming a closed-loop system. Productivity in the continuous process was higher compared to a batch one, with space–time yields of up to 1228 ± 65 µmol/L/h. A temperature of 70 °C resulted in the highest glucose-6-O-decanoate concentration in the Packed Bed Reactor (PBR). Consequently, the design of a continuous biocatalytic production is a step towards a more competitive glycolipid synthesis in the aim for industrialization.
32
Wiegandt, Herbert. "Insect glycolipids." Biochimica et Biophysica Acta (BBA) - Lipids and Lipid Metabolism 1123, no. 2 (January 1992): 117–26. http://dx.doi.org/10.1016/0005-2760(92)90101-z.
33
Kostetsky, Eduard, Natalia Chopenko, Maria Barkina, Peter Velansky, and Nina Sanina. "Fatty Acid Composition and Thermotropic Behavior of Glycolipids and Other Membrane Lipids of Ulva lactuca (Chlorophyta) Inhabiting Different Climatic Zones." Marine Drugs 16, no. 12 (December 7, 2018): 494. http://dx.doi.org/10.3390/md16120494.
Анотація:
Increasing global temperatures are expected to increase the risk of extinction of various species due to acceleration in the pace of shifting climate zones. Nevertheless, there is no information on the physicochemical properties of membrane lipids that enable the adaptation of the algae to different climatic zones. The present work aimed to compare fatty acid composition and thermal transitions of membrane lipids from green macroalgae Ulva lactuca harvested in the Sea of Japan and the Adriatic Sea in summer. U. lactuca inhabiting the Adriatic Sea had bleached parts of thalli which were completely devoid of chloroplast glycolipids. The adaptation to a warmer climatic zone was also accompanied by a significant decrease in the ratio between unsaturated and saturated fatty acids (UFA/SFA) of membrane lipids, especially in bleached thalli. Hence, bleaching of algae is probably associated with the significant decrease of the UFA/SFA ratio in glycolipids. The decreasing ratio of n-3/n-6 polyunsaturated fatty acids (PUFAs) was observed in extra-plastidial lipids and only in the major glycolipid, non-lamellar monogalactosyldiacylglycerol. The opposite thermotropic behavior of non-lamellar and lamellar glycolipids can contribute to maintenance of the highly dynamic structure of thylakoid membranes of algae in response to the increasing temperatures of climatic zones.
34
Mahon, Robert N., Roxana E. Rojas, Scott A. Fulton, Jennifer L. Franko, Clifford V. Harding, and W. Henry Boom. "Mycobacterium tuberculosis Cell Wall Glycolipids Directly Inhibit CD4+ T-Cell Activation by Interfering with Proximal T-Cell-Receptor Signaling." Infection and Immunity 77, no. 10 (August 3, 2009): 4574–83. http://dx.doi.org/10.1128/iai.00222-09.
Анотація:
ABSTRACT Immune evasion is required for Mycobacterium tuberculosis to survive in the face of robust adaptive CD4+ T-cell responses. We have previously shown that M. tuberculosis can indirectly inhibit CD4+ T cells by suppressing the major histocompatibility complex class II antigen-presenting cell function of macrophages. This study was undertaken to determine if M. tuberculosis could directly inhibit CD4+ T-cell activation. Murine CD4+ T cells were purified from spleens by negative immunoaffinity selection followed by flow sorting. Purified CD4+ T cells were activated for 16 to 48 h with CD3 and CD28 monoclonal antibodies in the presence or absence of M. tuberculosis and its subcellular fractions. CD4+ T-cell activation was measured by interleukin 2 production, proliferation, and expression of activation markers, all of which were decreased in the presence of M. tuberculosis. Fractionation identified that M. tuberculosis cell wall glycolipids, specifically, phosphatidylinositol mannoside and mannose-capped lipoarabinomannan, were potent inhibitors. Glycolipid-mediated inhibition was not dependent on Toll-like receptor signaling and could be bypassed through stimulation with phorbol 12-myristate 13-acetate and ionomycin. ZAP-70 phosphorylation was decreased in the presence of M. tuberculosis glycolipids, indicating that M. tuberculosis glycolipids directly inhibited CD4+ T-cell activation by interfering with proximal T-cell-receptor signaling.
35
Madassery, J. V., B. Gillard, D. M. Marcus, and M. H. Nahm. "Subpopulations of B cells in germinal centers. III. HJ6, a monoclonal antibody, binds globoside and a subpopulation of germinal center B cells." Journal of Immunology 147, no. 3 (August 1, 1991): 823–29. http://dx.doi.org/10.4049/jimmunol.147.3.823.
Анотація:
Abstract To identify surface Ag uniquely expressed on human germinal center B cells, we produced a mouse mAb, HJ6. When tonsillar lymphocytes were examined, HJ6 did not label T cells and labeled only about half of PNA+ B cells that were HK23-. HJ6 did not label mononuclear cells from peripheral blood, splenocytes, and any of 29 cell lines including 23 B cell lines. This binding pattern of HJ6 was very similar to that of a mAb named 5B5. It was shown previously that 5B5 bound a glycolipid named CTH (CD77) and its Ag was expressed on HK23- PNA+ tonsillar lymphocytes and Burkitt's lymphoma cell lines. Despite the similarity, HJ6 differed from 5B5: HJ6 did not stain Burkitt's lymphoma cell lines and stained PNA+ tonsillar lymphocytes in the presence of a large concentration of galactose. When its binding to isolated glycolipids was studied, HJ6 was found to bind globoside and Forssman Ag and not to other glycolipids including CTH. When its binding to neutral glycolipids extracted from tonsillar lymphocytes was studied, HJ6 bound only globoside; Forssman Ag was not detected in tonsillar lymphocytes. Taken together, we conclude that globoside is a B cell Ag expressed on a subpopulation of germinal center B cells.
36
Nagahori, Noriko, Kenichi Niikura, Reiko Sadamoto, Kenji Monde, and Shin-Ichiro Nishimura. "Synthesis of Photopolymerizable Glycolipids and their Application as Scaffolds to Immobilize Proteins with a Micron-Sized Pattern." Australian Journal of Chemistry 56, no. 6 (2003): 567. http://dx.doi.org/10.1071/ch02182.
Анотація:
Photopolymerizable glycolipids incorporating ceramide- or amido-type linkers and able to form stable monolayers were efficiently synthesized by chemical and enzymatic methods. Glycolipid polymer films served as platforms for the immobilization of proteins through specific carbohydrate–protein interactions at the air–water interface. Carbohydrate-binding proteins deposited on the glycolipid film were observed by atomic force microscopy, which showed varying submicron-sized protein patterns such as dendrites, dots, and networks, depending on the lipid structure, membrane preparation process, and sugar density of the membrane. Surface plasmon resonance measurement confirmed that the subunit-type lectins immobilized on the glycolipid membranes exhibited the ability to interact specifically with carbohydrate ligands by using unoccupied binding sites.
37
OHKATSU, Yasukazu, Miho OZAWA, Yoshiko NUMATA, and Nobuhiro NAKAMURA. "Glycolipid Enzyme Models. X. Catalysis of Glycolipids with Amino Acid Residue." Journal of Japan Oil Chemists' Society 45, no. 6 (1996): 545–53. http://dx.doi.org/10.5650/jos1996.45.545.
38
Yang, Guangli, Richard W. Franck, Hoe-Sup Byun, Robert Bittman, Pranati Samadder, and Gilbert Arthur. "ConvergentC-Glycolipid Synthesis via the Ramberg−Bäcklund Reaction: Active Antiproliferative Glycolipids." Organic Letters 1, no. 13 (December 1999): 2149–51. http://dx.doi.org/10.1021/ol991211f.
39
Delavault, André, Katarina Ochs, Olga Gorte, Christoph Syldatk, Erwann Durand, and Katrin Ochsenreither. "Microwave-Assisted One-Pot Lipid Extraction and Glycolipid Production from Oleaginous Yeast Saitozyma podzolica in Sugar Alcohol-Based Media." Molecules 26, no. 2 (January 18, 2021): 470. http://dx.doi.org/10.3390/molecules26020470.
Анотація:
Glycolipids are non-ionic surfactants occurring in numerous products of daily life. Due to their surface-activity, emulsifying properties, and foaming abilities, they can be applied in food, cosmetics, and pharmaceuticals. Enzymatic synthesis of glycolipids based on carbohydrates and free fatty acids or esters is often catalyzed using certain acyltransferases in reaction media of low water activity, e.g., organic solvents or notably Deep Eutectic Systems (DESs). Existing reports describing integrated processes for glycolipid production from renewables use many reaction steps, therefore this study aims at simplifying the procedure. By using microwave dielectric heating, DESs preparation was first accelerated considerably. A comparative study revealed a preparation time on average 16-fold faster than the conventional heating method in an incubator. Furthermore, lipids from robust oleaginous yeast biomass were successfully extracted up to 70% without using the pre-treatment method for cell disruption, limiting logically the energy input necessary for such process. Acidified DESs consisting of either xylitol or sorbitol and choline chloride mediated the one-pot process, allowing subsequent conversion of the lipids into mono-acylated palmitate, oleate, linoleate, and stearate sugar alcohol esters. Thus, we show strong evidence that addition of immobilized Candida antarctica Lipase B (Novozym 435®), in acidified DES mixture, enables a simplified and fast glycolipid synthesis using directly oleaginous yeast biomass.
40
Ziegler, M., S. Teneberg, S. Witt, B. Ziegler, B. Hehmke, K. D. Kohnert, J. Egeberg, K. A. Karlsson, and A. Lernmark. "Islet beta-cytotoxic monoclonal antibody against glycolipids in experimental diabetes induced by low dose streptozotocin and Freund's adjuvant." Journal of Immunology 140, no. 12 (June 15, 1988): 4144–50. http://dx.doi.org/10.4049/jimmunol.140.12.4144.
Анотація:
Abstract Diabetes was induced in BALB/c mice by four injections of a subdiabetogenic dose (40 mg/kg) of streptozotocin in combination with CFA. The treatment increased the plasma glucose from 5.8 +/- 0.1 to 22.1 +/- 1.3 mmol/liter (n = 9). The diabetic animals had circulating islet cell surface antibodies (75%), and a monoclonal islet cell surface IgM antibody, K56aF3, generated from one of the diabetic BALB/c mice, mediated C-Dependent cytotoxicity against insulin-producing cells and inhibited glucose-stimulated insulin release from isolated rat islets. Solid phase assay on thin layer chromatograms showed no binding of the K56aF3 antibody to glycolipids prepared from relevant cells. However, testing against a series of glycolipids of various non-pancreatic origins showed a preferential binding to a nine-sugar glycolipid isolated from human erythrocytes carrying an unusual blood group A determinant (type 3). It is suggested that this mAb may be associated with the development of diabetes following a combination of polyclonal activation and non-diabetogenic doses of streptozotocin.
41
Hartmann, Evamarie, Clifford A. Lingwood, and Joachim Reidl. "Heat-Inducible Surface Stress Protein (Hsp70) Mediates Sulfatide Recognition of the Respiratory Pathogen Haemophilus influenzae." Infection and Immunity 69, no. 5 (May 1, 2001): 3438–41. http://dx.doi.org/10.1128/iai.69.5.3438-3441.2001.
Анотація:
ABSTRACT The in vitro glycolipid binding specificity of clinical strains of nontypeable Haemophilus influenzae is altered to include sulfated glycolipids following a brief heat shock. We have constructed, expressed, and purified a recombinant protein of H. influenzae Hsp70, which showed significant specific binding to sulfated galactolipids in vitro. Furthermore, indirect immunofluorescence demonstrates that Hsp70 proteins are surface exposed in H. influenzae only after heat shock and are contained in the outer membrane protein fractions.
42
Gerasimenko, E. O., M. V. Slobodyanik, S. A. Sonin, and P. О. Popkova. "Glycolipids as a promising ingredient in food and pharmaceutical technologies." New Technologies 18, no. 4 (February 23, 2023): 35–50. http://dx.doi.org/10.47370/2072-0920-2022-18-4-35-50.
Анотація:
The relevance of the analysis of scientific publications devoted to the study of the composition, properties, methods of preparation, areas of application, as well as the qualitative and quantitative identification of glycolipids is determined by the prospects for their use as alternative natural surfactants. Glycolipids possessing comparable surfactant properties with widely used surfactants of a petrochemical nature, and distinguished by the absence of toxicity and environmental friendliness, exhibit pronounced physiological and functional properties.Currently, there are no systematic data covering various aspects of the composition, physicochemical properties of glycolipids.The purpose of this research is to clarify the classification of glycolipids, to summarize data on the advantages and disadvantages of various industrial methods for obtaining glycolipids; systematization of data on the properties of glycolipids by application; identification of the most effective methods for the qualitative and quantitative identification of glycolipids.Particular attention is paid to the analysis of data on the possibility of isolating glycolipids from plant materials, including secondary resources of the oil and fat industry.The data presented in the review indicate that glycolipids, including those isolated from plant materials, are characterized by a high biotechnological potential for their use in the creation of pharmaceuticals, cosmetics, and functional foods.Of the known methods for the industrial production of glycolipids, currently the most common and cost-effective methods are those based on microbiological and enzymatic synthesis.Promising raw materials for the production of glycolipids are secondary products of processing of oilseeds – phosphatide emulsions and phosphatide concentrates containing up to 5% glycolipids in their composition. There are currently no methods for obtaining glycolipids from this type of raw material.Of the known methods for the qualitative and quantitative identification of glycolipids (TLC, HPTLC, HPLC, NMR), the most promising method is high-resolution NMR spectroscopy, as it is the most informative, rapid and accurate.
43
Redman, C. A., P. Schneider, A. Mehlert, and M. A. J. Ferguson. "The glycoinositol-phospholipids of Phytomonas." Biochemical Journal 311, no. 2 (October 15, 1995): 495–503. http://dx.doi.org/10.1042/bj3110495.
Анотація:
The Phytomonas spp. are trypanosomatid parasites of plants. A polar glycolipid fraction of a Phytomonas sp., isolated from the plant Euphorbia characias and grown in culture, was fractionated into four major glycolipid species (Phy 1-4). The glycolipids were analysed by chemical and enzymic modifications, composition and methylation analyses, electrospray mass spectrometry and microsequencing after HNO2 deamination and NaB3H4 reduction. The water-soluble headgroup of the Phy2 glycolipid was also analysed by 1H NMR. All four glycolipids were shown to be glycoinositol-phospholipids (GIPLs) with phosphatidylinositol (PI) moieties containing the fully saturated alkylacylglycerol lipids 1-O-hexadecyl-2-O-palmitoylglycerol and 1-O-hexadecyl-2-O-stearoylglycerol. The structures of the Phy 1-4 GIPLs are: Man alpha 1-2Man alpha 1-6Man alpha 1-4GlcN alpha 1-6PI, Glc alpha 1-2(NH2-CH2CH2-HPO4-)Man alpha 1-2Man alpha 1-6Man alpha 1-4GlcN alpha 1-6PI, [formula: see text] Glc alpha 1-2(NH2CH2CH2-HPO4-)Man alpha 1-2Man alpha 1-6Man alpha 1-4(NH2-CH2CH2-HPO4-)GlcN alpha 1-6PI [formula: see text] and Glc alpha 1-2Glc alpha 1-2(NH2CH2-CH2-HPO4-)Man alpha 1-2Man alpha 1-6Man alpha 1-4(NH2CH2CH2-HPO4-)-GlcN alpha 1-6PI. [formula: see text] The Phytomonas GIPLs represent a novel series of structures. This is the first description of the chemical structure of cell-surface molecules of this plant pathogen. The Phytomonas GIPLs are compared with those of other trypanosomatid parasites and are discussed with respect to trypanosomatid phylogenetic relationships.
44
Burdin, Nicolas, Laurent Brossay, Yasuhiko Koezuka, Stephen T. Smiley, Michael J. Grusby, Ming Gui, Masaru Taniguchi, Kyoko Hayakawa та Mitchell Kronenberg. "Selective Ability of Mouse CD1 to Present Glycolipids: α-Galactosylceramide Specifically Stimulates Vα14+ NK T Lymphocytes". Journal of Immunology 161, № 7 (1 жовтня 1998): 3271–81. http://dx.doi.org/10.4049/jimmunol.161.7.3271.
Анотація:
Abstract Mouse CD1 (mCD1) glycoproteins are known to present peptides, while human CD1 molecules present glycolipids. In mice, mCD1-autoreactive NK T cells play critical roles in various immune responses, through the secretion of high amounts of cytokines. This study was initiated to determine whether glycolipids are involved in the autorecognition of mCD1 by NK T cells. α-Galactosylceramide (α-GalCer) was the only glycolipid tested capable of eliciting an mCD1-restricted response by splenic T cells. Moreover, splenic T cells derived from mCD1-deficient mice were not stimulated by α-GalCer, suggesting that the responsive T cells are selected by mCD1. Using cytoflow techniques, we confirmed that, in response to α-GalCer, IFN-γ-secreting cells displayed an NK T cell phenotype. The predominance of IFN-γ vs IL-4, however, is determined by the type of mCD1+ APC, suggesting the potential for APC regulation of cytokine production by NK T cells. Among a panel of 10 mCD1-autoreactive T cell hybridomas, only the ones that express the typical Vα14Jα281 TCR rearrangement of NK T cells responded to α-GalCer. Fixation or treatment of mCD1+ APCs with an inhibitor of endosomal acidification and the use of mCD1 mutants unable to traffic through endosome still allowed α-GalCer to stimulate NK T cells. Thus, endosomal trafficking and Ag processing are not required for glycolipid recognition. In summary, α-GalCer might be the autologous ligand, or a mimic of a glycolipid ligand, involved in the mCD1-mediated stimulation of NK T cells.
45
Weiss, J. B., J. L. Magnani, and M. Strand. "Identification of Schistosoma mansoni glycolipids that share immunogenic carbohydrate epitopes with glycoproteins." Journal of Immunology 136, no. 11 (June 1, 1986): 4275–82. http://dx.doi.org/10.4049/jimmunol.136.11.4275.
Анотація:
Abstract The immunoreactivity of sera of infected hosts against glycolipids derived from Schistosoma mansoni eggs, adult male worms, and cercariae was analyzed by immunostaining of glycolipids resolved by high-performance thin-layer chromatography. Eggs contained the greatest number of immunogenic glycolipids and bound the largest proportion of serum antibodies. Virtually all of the immunogenic egg glycolipids were neutrally charged and contained oligosaccharide chains larger in size than five sugar residues. The glycolipids of each developmental stage were shown by use of five monoclonal antibodies to share schistosome-specific carbohydrate epitopes that were also present on glycoproteins. Several of the carbohydrate epitopes were expressed throughout the life cycle, yet the overall structures of the glycolipids were not conserved. Quantitative analyses by solid-phase binding assays indicated that the carbohydrate epitopes were differentially expressed between the glycolipids and glycoproteins of developmental stages. Sera from infected humans and mice both contained very high levels of anti-carbohydrate antibodies that were reactive with the glycolipids, irrespective of the stage or intensity of disease. Mice harboring unisexual infections of either male or female worms also recognized the egg glycolipids in a pattern indistinguishable from that of patently infected mice. A greater proportion of the humoral response against egg antigens in infected humans was directed against protein determinants, as compared with infected mice.
46
Spada, Franca M., Yasuhiko Koezuka, and Steven A. Porcelli. "CD1d-restricted Recognition of Synthetic Glycolipid Antigens by Human Natural Killer T Cells." Journal of Experimental Medicine 188, no. 8 (October 19, 1998): 1529–34. http://dx.doi.org/10.1084/jem.188.8.1529.
Анотація:
A conserved subset of mature circulating T cells in humans expresses an invariant Vα24-JαQ T cell receptor (TCR)-α chain rearrangement and several natural killer (NK) locus–encoded C-type lectins. These human T cells appear to be precise homologues of the subset of NK1.1+ TCR-α/β+ T cells, often referred to as NK T cells, which was initially identified in mice. Here we show that human NK T cell clones are strongly and specifically activated by the same synthetic glycolipid antigens as have been shown recently to stimulate murine NK T cells. Responses of human NK T cells to these synthetic glycolipids, consisting of certain α-anomeric sugars conjugated to an acylated phytosphingosine base, required presentation by antigen-presenting cells expressing the major histocompatibility complex class I–like CD1d protein. Presentation of synthetic glycolipid antigens to human NK T cells required internalization of the glycolipids by the antigen-presenting cell and normal endosomal targeting of CD1d. Recognition of these compounds by human NK T cells triggered proliferation, cytokine release, and cytotoxic activity. These results demonstrate a striking parallel in the specificity of NK T cells in humans and mice, thus providing further insight into the potential mechanisms of immune recognition by NK T cells and the immunological function of this unique T cell subset.
47
Buxbaum, Laurence. "Leishmania mexicana infection induces antibody responses to parasite surface glycolipids that can induce IL-10 and suppress IL-12 from macrophages (37.25)." Journal of Immunology 184, no. 1_Supplement (April 1, 2010): 37.25. http://dx.doi.org/10.4049/jimmunol.184.supp.37.25.
Анотація:
Abstract Chronic disease of mice caused by the protozoan parasite Leishmania mexicana requires IL-10 and FcγRIII. Immune complexes consisting of IgG bound to the surface of Leishmania amastigotes can induce IL-10 and suppress IL-12 production from macrophages. However, the targets of these antibodies and the kinetics of their production are not known. Several groups have attempted, without success, to identify surface proteins on the amastigote form of the parasite to which IgG can bind. Using ELISA and thin layer chromatography (TLC) immunoblot methods we now show that parasite glycoinositol phospholipids (GIPLs) of L. mexicana are recognized by IgG1 by 6 weeks of infection with a rapid increase between 14-16 wks, consistent with the timing of chronic disease in C57BL/6 mice vs. healing in FcγRIII KO mice. We found that a single prominent spot on TLC is recognized by mouse serum of infected mice and that the glycolipid has a glycosyl phosphatidylinositol (GPI) structure as assessed by GPI-PLC and GPI-PLD susceptibility. Alpha-mannosidase treatment changed the mobility of the recognized glycolipid, indicating that a branched mannose occurs in the structure, but is not required for IgG binding. Further characterization of the target glycolipids will have important implications for vaccine development as well as elucidating the poorly understood role of glycolipids in immunology. Funded by VA Merit, the University of Pennsylvania, and NIH R01-AI081717.
48
Han, Dong, and Heng-Lin Cui. "Salinibaculum litoreum gen. nov., sp. nov., isolated from salted brown alga Laminaria." International Journal of Systematic and Evolutionary Microbiology 70, no. 4 (April 1, 2020): 2879–87. http://dx.doi.org/10.1099/ijsem.0.004114.
Анотація:
A novel Gram-stain-negative, aerobic and rod-shaped halophilic archaeon, designated HD8-45T, was isolated from the red brine of salted brown alga Laminaria produced at Dalian, PR China. According to the results of 16S rRNA gene and rpoB′ gene sequence comparisons, strain HD8-45T showed the highest sequence similarity to the corresponding genes of Salinirussus salinus YGH44T (95.1 and 85.2 % similarities, respectively), Halovenus aranensis EB27T (91.2 and 86.0 % similarities, respectively). The low sequence similarity and the phylogeny implied the novel generic status of strain HD8-45T. Genomic relatedness analyses showed that strain HD8-45T were clearly distinguished from other species in the order Halobacteriales , with average nucleotide identity, amino acid identity and in silico DNA–DNA hybridization values not more than 75.1, 65.6 and 21.5 %. The polar lipid pattern contained phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, two major glycolipids and two minor glycolipids. The two major glycolipids and a minor glycolipid were chromatographically identical to disulfated mannosyl glucosyl diether, sulfated mannosyl glucosyl diether and mannosyl glucosyl diether, respectively. The major respiratory quinones were menaquinone MK-8 and MK-8(H2). The DNA G+C content was 62.0 mol% (Tm ) and 61.9 mol% (genome). All these results showed that strain HD8-45T represents a novel species of a new genus in the order Halobacteriales , for which the name Salinibaculum litoreum gen. nov., sp. nov. is proposed. The type strain of Salinibaculum litoreum is HD8-45T (=CGMCC 1.15328T=JCM 31107T).
49
Diercks, Hannah, Adrian Semeniuk, Nicolas Gisch, Hermann Moll, Katarzyna A. Duda, and Georg Hölzl. "Accumulation of Novel Glycolipids and Ornithine Lipids in Mesorhizobium loti under Phosphate Deprivation." Journal of Bacteriology 197, no. 3 (November 17, 2014): 497–509. http://dx.doi.org/10.1128/jb.02004-14.
Анотація:
Glycolipids are found mainly in photosynthetic organisms (plants, algae, and cyanobacteria), Gram-positive bacteria, and a few other bacterial phyla. They serve as membrane lipids and play a role under phosphate deprivation as surrogates for phospholipids.Mesorhizobium lotiaccumulates different di- and triglycosyl diacylglycerols, synthesized by the processive glycosyltransferase Pgt-Ml, and two so far unknown glycolipids, which were identified in this study by mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy asO-methyl-digalactosyl diacylglycerol (Me-DGD) and glucuronosyl diacylglycerol (GlcAD). Me-DGD is a novel glycolipid, whose synthesis depends on Pgt-Ml activity and the involvement of an unknown methyltransferase, while GlcAD is formed by a novel glycosyltransferase encoded by the open reading frame (ORF)mlr2668, using UDP-glucuronic acid as a sugar donor. Deletion mutants lacking GlcAD are not impaired in growth. Our data suggest that the different glycolipids inMesorhizobiumcan mutually replace each other. This may be an adaptation mechanism to enhance the competitiveness in natural environments. A further nonphospholipid inMesorhizobiumwas identified as a hydroxylated form of an ornithine lipid with the additional hydroxy group linked to the amide-bound fatty acid, introduced by the hydroxylase OlsD. The presence of this lipid has not been reported for rhizobia yet. The hydroxy group is placed on the C-2 position of the acyl chain as determined by NMR spectroscopy. Furthermore, the isolated ornithine lipids contained up to 80 to 90%d-configured ornithine, a stereoform so far undescribed in bacteria.
50
Singer, M. E. Vogt, and W. R. Finnerty. "Physiology of biosurfactant synthesis by Rhodococcus species H13-A." Canadian Journal of Microbiology 36, no. 11 (November 1, 1990): 741–45. http://dx.doi.org/10.1139/m90-127.
Анотація:
The physiology of biosurfactant synthesis by a soil isolate, identified as a Rhodococcus species, is described. The biosurfactant is a surface-active glycolipid produced during the stationary growth phase of Rhodococcus species H13-A on n-alkanes and fatty alcohols in response to limiting ammonium ion concentrations. Hexadecane-grown cells produced increasing amounts of extracellular glycolipid when the carbon to nitrogen ratio (C/N) was increased from 1.7 to 3.4. The increase in extracellular glycolipid in hexadecane-grown cells correlated with a decrease in the interfacial tension of the spent growth medium to values less than 5 mN/m. Significant levels of extracellular glycolipid were not detected in the spent growth medium of cells grown on triglycerides, fatty acids, ethanol, organic acids, or carbohydrates. Rhodococcus species H13-A contains the three indigenous plasmids pMVS100, pMVS200, and pMVS300, with neither pMVS200 nor pMVS300 being involved in glycolipid synthesis or hexadecane dissimilation. The role of pMVS100 remains undetermined. Key words: biosurfactants, glycolipids, trehalose lipids, Rhodococcus.