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PubMed1984

Dodecylglycerol. A new type of antibacterial agent which stimulates autolysin activity in Streptococcus faecium ATCC 9790.

Dodecylglycerol has a minimum inhibitory concentration of 4 micrograms/ml compared to 9 micrograms/ml for monolaurin (dodecanoylglycerol) with Streptococcus faecium ATCC 9790 as the test organism. The greater potency of dodecylglycerol can be correlated to its greater retention by the cell. Gram-positive bacteria were more susceptible than Gram-negative bacteria to dodecylglycerol. The antibacterial action of dodecylglycerol is not through the physical dissolution of cell walls, but rather as an enzymatic effector. The autolysin activity of whole cells of S. faecium was greatly stimulated by dodecylglycerol. The stimulation of autolytic activity and inhibition of growth respond in parallel to different concentrations of dodecylglycerol, to dodecylglycerol versus some poorer effector such as monolaurin or a glycerol alkyl ether with a longer or shorter fatty alkyl side chain than dodecanol, and to the antagonistic effects of diphosphatidlyglycerol. This close relationship implies that the stimulation of autolysin activity could be a primary, but not necessarily the only, mechanism by which dodecylglycerol and related compounds exert their antibacterial activity. However, the autolysin activity is not stimulated by a direct interaction between the enzyme and dodecylglycerol. A non-wall entity, such as a proteinase, has been implicated as an intermediary (Ved, H. S., Gustow, E., and Pieringer, R. A. (1984) J. Biol. Chem. 259, 8122-8124).

Amidohydrolases↗
PubMed1984

The involvement of the proteinase of Streptococcus faecium ATCC 9790 in the stimulation of its autolysin activity by dodecylglycerol.

Treatment of Streptococcus faecium ATCC 9790 with 3.5 micrograms/ml of dodecylglycerol produces a nonwall entity found in the 25,000 X g supernatant cell fraction which activates the autolysin activity of S. faecium. The stimulation of the autolysin activity by dodecylglycerol mimics the activation of the autolysin from a latent to an active form by trypsin and other proteolytic enzymes. This stimulation of autolytic activity by dodecylglycerol can be reversed by specific proteinase inhibitors. Dodecylglycerol also markedly stimulates the proteinase activity endogenous to S. faecium, and this stimulation can be reversed by several proteinase inhibitors. It is concluded that one primary antibacterial mode of action of dodecylglycerol is to stimulate the proteinase of S. faecium which activates the cell's autolysin and thereby prevents bacterial growth.

Amidohydrolases↗
PubMed1981

The effect of surfactants upon the activity and distribution of glucosyltransferase in Streptococcus mutans 6715.

A modified Somogyi-Nelson procedure was used to determine the amount of reducing sugar produced during the reaction of S. mutans 6715 glucosyltransferase (GTF) with sucrose. This technique is an indirect measure of GTF activity and was used to determine the effects of the surfactants glycerol monolaurin (GML) and sodium lauryl sulfate (SLS) upon crude extracellular GTF. GML at 5, 10, and 15 micrograms/ml reduced culture filtrate GTF enzyme activity to an average of 81% of the control value. SLS at the only concentration tested (15 micrograms/ml) also caused a reduction, resulting in a GTF activity level that was 82% of the control value. Secondly, S. mutans 6715 cultures were grown in a medium containing Tween 80, or SLS. The cell-free culture filtrate and the cell-pellet were assayed separately for GTF activity. GML in the medium produced a decrease in culture filtrate GTF activity and an increased cell-pellet activity. The total (whole culture) activity for culture broths was 89% to 90% of the control value when 5, 10, or 15 micrograms/ml GML were added. Tween 80 supplemented culture medium resulted in increased culture filtrate GTF, while levels measured in the cell-pellet were decreased. Overall, Tween 80 caused a large increase in whole culture GTF activity. Cell cultures containing SLS at 15 micrograms/ml resulted in no change in the GTF activity as compared to the control, nor was there any change in the percent of GTF in the culture filtrate versus the percent which was in the cell-pellet. Higher concentrations of SLS could not be tested due to the inhibitory effect on cellular growth.

Fatty Alcohols↗
PubMedDate not supplied

[Phase transitions in lyotropic liquid crystals: bilayer and micelle stability].

A model for describing hydrophile and hydrophobic interactions was introduced. On the basis of this model a phase diagram was calculated for transitions of homogeneous mixture amphyphyl--water into pure, intermediate and isotropic phases. Coefficients of the model introduced were found from the comparison with the experimental data. A relative role of electrostatic interaction was evaluated and compared with hydrophile and hydrophobic ones.

Chemical Phenomena↗
PubMed1995

Inability of two topical treatments to influence the course of experimentally induced dermatophytosis in cats.

An experimental model of dermatophytosis was used to compare the efficacy of 2 topical antifungal treatments against Microsporum canis infection in cats. Infection was established in 24 cats by topical application of 10(5) M canis macroconidia to the skin of the lateral part of the abdomen under an occlusive bandage. Three groups of 6 cats each then were treated twice weekly for 18 weeks with chlorhexidine shampoo and dip, detergent shampoo vehicle only, or glyceryl monolaurate shampoo. Six cats were left untreated as controls. The experimentally induced infections strongly resembled naturally developing infections of moderate to severe nature. Signs of infection peaked in severity at 5 weeks after inoculation, then gradually resolved over 7 to 16 additional weeks. Dermatophytes were consistently isolated on culture for at least 8 weeks of treatment. Mycologic cure (defined as lack of dermatophyte isolation on 3 successive weekly cultures) was attained in 8 cats at the end of 18 weeks of treatment. Infections appeared to resolve at equivalent rates in all groups of cats, including controls. Consistent or meaningful significant differences in variables such as lesion size, clinical sign score, or total infection score were not found between treated and control groups. Our study revealed that this topical treatment regimen with chlorhexidine or glyceryl monolaurate is ineffective against M canis infection in cats.

Administration, Topical↗
PubMed1993

Antiviral phospholipids. Anti-HIV drugs conjugated to the glycerobackbone of phospholipids.

Heteroatom fatty acid analogs of myristic acid containing oxygen or sulfur substituted for the alkyl methylene groups inhibit replication of the human immunodeficiency virus (HIV) in infected cells by acting as alternative substrates during the viral protein myristoylation event. In this class of compounds, 12-methoxydodecanoic acid is the most potent compound but is approximately 10(3)-fold less active than azidothymidine. The antiviral activity of 12-methoxydodecanoic acid can be enhanced > 40-fold by preparing L-alpha-phosphatidylethanolamine containing 12-methoxydodecanoic acid in both alkyl chains. In addition, the diacylated L-alpha-phosphatidylcholine analog containing 12-methoxydodecanoic acid in both alkyl chains (i) has a 15-fold better antiviral selectivity, (ii) is 7-fold more potent, and (iii) is 10-100-fold more synergistic with azidothymidine than 12-methoxydodecanoic acid. Because of potent synergism, the antiviral selectivity of the diacylated L-alpha-phosphatidylcholine analog is > 10(4) when coadministered with azidothymidine. Phospholipid conjugates are chiral at the C-2 carbon of the glycerol backbone and most interesting is the observation that both the D- and L-isomers of phosphatidylcholine, phosphatidylglycerol, phosphatidic acid, and phosphatidylserine have approximately equal antiviral activity. Phospholipase A2 stereospecifically hydrolyzes only the L isomer of phospholipids and similar activity for both the D- and L- phospholipid isomers suggests that phospholipase A2 is not the rate-limiting enzyme for release of the drugs in vivo.

Antiviral Agents↗
PubMed1994

A defect in the inflammation-primed macrophage-activation cascade in osteopetrotic rats.

Macrophages were activated by administration of lysophosphatidylcholine (lyso-Pc) or dodecylglycerol (DDG) to wild-type rats but not in osteopetrotic (op) mutant rats. In vitro treatment of wild-type rat peritoneal cells with lyso-Pc or DDG efficiently activated macrophages whereas treatment of op mutant rat peritoneal cells with lyso-Pc or DDG did not activate macrophages. The inflammation-primed macrophage activation cascade in rats requires participation of B lymphocytes and vitamin D binding protein (DBP). Lyso-Pc-inducible beta-galactosidase of wild-type rat B lymphocytes can convert DBP to the macrophage-activating factor (MAF), whereas B lymphocytes of the op mutant rats were shown to be deficient in lyso-Pc-inducible beta-galactosidase. DBP is conserved among mammalian species. Treatment of human DBP (Gc1 protein) with commercial glycosidases yields an extremely high titrated MAF as assayed on mouse and rat macrophages. Because the enzymatically generated MAF (GcMAF) bypasses the role of lymphocytes in macrophage activation, the op mutant rat macrophages were efficiently activated by administration of a small quantity (100 pg/rat) of GcMAF. Likewise, in vitro treatment of op rat peritoneal cells with as little as 40 pg GcMAF/ml activated macrophages.

Animals↗
PubMed1993

Conversion of vitamin D3 binding protein (group-specific component) to a macrophage activating factor by the stepwise action of beta-galactosidase of B cells and sialidase of T cells.

Highly conserved DBP (human DBP is known as Gc) of serum alpha 2-globulin fraction can be converted to a potent macrophage activating factor by stepwise modification of Gc glycoprotein with beta-galactosidase of B cells and sialidase of T cells. These glycosidases, beta-galactosidase and sialidase, are membrane bound and not soluble in culture medium. Thus, consecutive contact of Gc protein with B cells and T cells, presumably via specific receptors, is required for conversion of Gc glycoprotein to the macrophage activating factor. The essential role of T cell sialidase in macrophage activation was confirmed by the finding that peritoneal nonadherent cells of SM/J mouse, whose T cells are deficient in sialidase activity, were unable to convert Gc protein to the macrophage activating factor and thus did not activate macrophages. Treatment with sialidase of a conditioned medium of lipid metabolite-treated SM/J mouse nonadherent cells efficiently generated the macrophage activating factor. When Gc protein was first treated with soluble or immobilized sialidase and used in a medium for 2 h cultivation of lipid metabolite-treated SM/J mouse nonadherent cells or BALB/c mouse B cells, the resultant conditioned media contained a large amount of the macrophage activating factor. These results support the hypothesis that Gc protein carries a dibranched trisaccharide with galactose and sialic acid termini.

Animals↗
PubMed1996

Effect of phospholipids on the structure of Triatoma infestans lipophorin studied by fluorescence methods.

To study the role of phospholipids in the lipophorin structure, they were removed by phospholipase A2 treatment. Fluorescence lifetimes and accessibility to acrylamide quenching of different diphenylhexatrienyl derivatives, which were used as analogues of the different lipid components, indicate a surface localization of phospholipids and a distribution of diacylglycerols between the core and the surface, the surface fraction being increased by the phospholipase A2 treatment. The rotational behavior of these probes, studied by differential polarized phase fluorescence, indicates a high lipid order not only in the surface layer where phospholipids are located, but also in the core occupied by diacylglycerols and hydrocarbons. Phospholipid depletion increases the order only in the external region of the surface layer. Energy transfer from apolipoprotein tryptophan residues to several fluorescent acceptors indicates that phospholipid depletion produces a re-accommodation of the apoproteins. A decreased mobility of the water in the interfacial region is also produced by the phospholipase A2 treatment as it is reported by the fluorescence of 6-lauroyl-2-dimethylaminonaphthalene. This work shows that phospholipase A2 treatment of T. infestans lipophorin results in stable particles with an increased diacylglycerol to phospholipid ratio in the surface lipid layer. The modified particles are possibly stabilized by a conformational change in the apolipoproteins.

2-Naphthylamine↗
PubMed1997

Effect of 19-norandrostenololylaurate on semen characteristics of colts.

The long-term effects of the anabolic steroid 19-norandrostenololylaurate on semen characteristics of Finnhorse colts were studied in 3 experiments. Semen was collected initially at 24 months of age and then twice a year. In experiment I, 500 mg or 100 mg of steroid per animal was given every 3rd week from 12 or 16 months to 24 months of age. In colts treated with 500 mg of anabolic steroid every 3rd week, azoospermia was observed in 3 out of 5 colts in the first semen collections, immediately after the end of treatment. The other 2 colts had low sperm numbers and a high percentage of proximal droplets in relation to control animals. The 100 mg group was less affected by steroid treatment than the 500 mg group. The seminal changes were observed to be reversible. All of the colts had spermatozoa in their ejaculates 4 months after the end of treatment. Two years after cessation of treatment, sperm numbers in treated animals exceeded those in the control group. In experiment II, colts were treated from 7 months to 12 months of age with a dose of 1 mg/kg every 3rd week or 0.3 mg/kg every week. The first semen collections took place 12 months after the last treatment. The animals treated with 0.3 mg/kg every week were less affected than those treated with 1 mg/kg every 3rd week. In experiment III, animals were treated from 3 months to 8 months of age, and the interval from the last treatment to the first semen collection was 16 months. There were no significant differences between the groups in any of the semen parameters examined. In the last semen collection, the control animals had numerically higher spermatozoal concentration and progressive motility and less dead sperm than the treated animals. It was concluded that the adverse effects of steroid treatment on semen characteristics were reversible, at least in the groups treated at age 7-25 months.

Aging↗
PubMed1997

Effect of 19-norandrostenololylaurate on testicular growth in colts.

The effect of anabolic steroid on testicular growth was investigated in 3 experiments. In experiment I, 500 mg of the anabolic steroid was given to 4 colts and 100 mg to another 4 colts, every 3rd week, starting at age 16 months and ending at age 24 months. Six colts served as controls. Both treatments decreased total scrotal width (TSW) within 6 weeks. Seasonal testicular growth during spring partly overcame the effect of steroid treatment. Cessation of anabolic steroid treatment was followed by testicular growth at the same time as TSW in untreated colts was decreasing by virtue of the effect of the season. Four months after the last injection, TSW was smaller in the treated animals than in the untreated animals, but the difference was not statistically significant. In experiment II, steroid was given at a dose of 1 mg/kg every 3rd week to 4 colts and 0.3 mg/kg every week to 4 colts. Six colts served as controls. The animals were 7 months old at the start of treatment and 12 months old at the end of treatment. Treatments decreased testicular widths (TW), within 6-9 weeks. In this experiment, also, cessation of anabolic steroid treatment was followed by testicular growth. Twelve months after the last treatment, TW was smaller in treated than in untreated animals but the difference was not statistically significant. In experiment III, foals were used which were 3 months old at the start and 8 months old at the end of treatment. The steroid was given at a dose of 1 mg/kg every 3rd week to 3 foals. Three foals served as controls. Treatment decreased TW within 6 weeks. Cessation of treatment was followed by a slow testicular growth. Growth similar to that in control animals started after a delay of 4-5 months. TW in treated animals nearly reached TW in controls within 12 months of cessation of treatment.

Aging↗