Esters of trehalose from Corynebacterium diphtheriae: A modified purification procedure and studies on the structure of their constituent hydroxylated fatty acids

Role of trehalose dimycolate in recruitment of cells and modulation of production of cytokines and NO in tuberculosis

Mice treated with viable Mycobacterium tuberculosis with no glycolipid trehalose dimycolate (TDM) on the outer cell wall (delipidated M. tuberculosis) by intraperitoneal or intratracheal inoculation presented an intense recruitment of polymorphonuclear cells into the peritoneal cavity and an acute inflammatory reaction in the lungs, respectively. In addition, lung lesions were resolved around the 32nd day after intratracheal inoculation. TDM-loaded biodegradable poly-DL-lactide-coglycolide microspheres as well as TDM-coated charcoal particles induced an intense inflammatory reaction. In addition, high levels of interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-alpha), IL-12, IL-10, gamma interferon (IFN-gamma), and IL-4 production were detected in lung cells, and nitric oxide (NO) production was high in culture supernatants of bronchoalveolar lavage cells. These in vivo data were confirmed by in vitro experiments using peritoneal macrophages cultured in the presence of TDM adsorbed onto coverslips. High levels of IFN-gamma, IL-6, TNF-alpha, IL-12, IL-10, and NO were detected in the culture supernatants. Our results suggest that TDM contributes to persistence of infection through production of cytokines, which are important for the recruitment of inflammatory cells and maintenance of a granulomatous reaction. In addition, our findings are important for a better understanding of the immunostimulatory activity of TDM and its possible use as an adjuvant in experiments using DNA vaccine or gene therapy against tuberculosis.

Thermospray mass spectral analyses of corynomycolic acids and their derivatives

Thermospray mass spectral (TSP-MS) analyses were carried out on methyl corynomycolates, their 3-O-acetyl and 3-O-benzoyl derivatives, and on corynomycolic acids and their 3-O-acetyl derivatives, using an ion generating solvent system consisting of water/isopropanol (99:1, v/v) containing 0.1 M ammonium acetate. Methyl corynomycolates generated three groups of peaks corresponding to adducts M-18 + H, M + H and M + NH4, while two groups of peaks representing adducts M-60 + H and M + H + NH4 were seen in the spectra of 3-O-acetyl methyl corynomycolates. The 3-O-benzoyl methyl corynomycolates gave a series of peaks representing the adducts M-122 + H, M + 2H and M + H + NH4. In the spectra of 3-O-acetyl corynomycolic acids, a series of peaks which represented M-60 + H and M + NH4 was observed, and in turn, mass spectra of corynomycolic acids revealed peaks that represented the adducts M-18 + H and M + NH4. Therefore, methyl corynomycolates, 3-O-acyl derivatives of methyl corynomycolates,. 3-O-acetylated derivatives of corynomycolic acids and the underivatized corynomycolic acids all exhibited the formation of an adduct of the anhydro compounds. These anhydro forms were generated by a generalized process.

Composition and toxicity of diethyl ether soluble lipids from Nocardia asteroides GUH-2 and Nocardia asteroides 10905

Virulent Nocardia asteroides GUH-2 and avirulent N. asteroides 10905 contained 8.2% and 10.6% of diethyl ether soluble lipids (DESL) per dry cell mass, respectively. Intraperitoneal (i.p.) inoculation of 250 micrograms of DESL from GUH-2 dissolved in mineral oil was toxic to mice, resulting in weight loss and death of 100% of the animals (20/20) within 20 days. In contrast, DESL from 10905 had very little toxicity, and only one mouse (1/10) died within 30 days. Three fractions resulted from DESL by silicic acid column chromatography: (1) neutral lipids and fatty acids (NFA); (2) glycolipids (GL); and (3) phospholipids (PL). Each fraction dissolved in mineral oil was inoculated into mice as described above. The NFA and PL were not toxic. GL from 10905 had low toxicity (30% of the animals died, 3/10) whereas GL from GUH-2 expressed high toxicity (100% of the animals became cachetic and died, 10/10). GL from 10905 represented a minor component (0.6% of dry cell weight) whereas GL from GUH-2 was more prominent (1.5% of dry cell wt.). Approximately 95% of GL from GUH-2 had properties of an authentic trehalose-6,6'-dimycolate standard. Infrared spectrum of the major glycolipid (GUH-2 GL) had characteristic absorptions in the fingerprint region between 800 cm-1 and 1500 cm-1. Upon alkaline hydrolysis GUH-2 GL released 76% mycolic acids in the C50 size range plus 24% trehalose.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular weight determination of methyl esters of mycolic acids using thermospray mass spectrometry

Methyl esters of normal fatty acids, corynomycolate and corynomycolenate were used as model compounds for thermospray mass spectrometric procedures for molecular weight determination of the related nocardial mycolic acids. By using ammonium acetate at the positive ion generator, in both cases, a family of ions was produced. The following members were found and corresponded to the adducts: (1) M + H; M + NH4 and M + H + NH4 for methyl esters of normal fatty acids, whereas M + H, M + 2H and M + H + NH4 were the adducts most frequently observed with methyl corynomycolates. The methyl esters of C40-C48 mycolic acids from Rhodococcus rhodochrous exhibited prominent peaks corresponding to adducts M + H + NH4 whereas those corresponding to M + 2H showed slightly lower intensities. The structure M + H had no significant representatives with this subclass of mycolic acids. A similar pattern was observed with methyl esters of C50-C54 mycolic acids from Nocardia asteroides GUH-2. Ion peaks C50-C54 representing adducts M + 2H and M + H + NH4 prevailed in the mass spectrum. In this case, the intensities of peaks corresponding to M + 2H were slightly higher than those of the M + H + NH4. Essentially three main species of nocardomycolic acids were detected: (1) monounsaturated C50:1, C52:1 and C54:1; (2) diunsaturated C50:2, C52:2 and C54:2 and (3) triunsaturated C52:3 and C54:3 mycolic acids. The most abundant mycolic acid was C52:2 followed in decreasing abundance by C52:1, C54:2, C50:2, C52:3 and C54:3 mycolic acids.

Tumor necrosis factor and macrophage activation are important in clearance of Nocardia brasiliensis from the livers and spleens of mice

The roles of tumor necrosis factor (TNF) and macrophage activation in clearance of Nocardia brasiliensis from BALB/c mouse livers and spleens were evaluated. TNF activity was detectable in sera from animals at all stages of infection. Treatment of infected mice with an antiserum against TNF significantly enhanced the experimental infection as judged by enumeration of CFU in the spleens and livers of infected mice. In another set of experiments, a population of activated macrophages from the peritoneal cavities of N. brasiliensis-infected mice was studied by using a cytostatic assay. The observed cytotoxic activity of these activated macrophages against L929 cells was mediated by TNF, since this activity was inhibited by anti-TNF antiserum treatment. The level of TNF activity generated in vitro in the presence of lipopolysaccharide (LPS) by peritoneal macrophages from infected mice was higher than that of adherent peritoneal cells obtained from normal mice after challenge with LPS. When the nocardiacidal activity of peritoneal cells from N. brasiliensis-infected mice was estimated in vitro, a significant decrease in the number of CFU recovered was observed. Moreover, nocardiacidal activity of peritoneal cells obtained from N. brasiliensis-infected mice previously treated with anti-TNF antiserum was significantly reduced compared with the activity of cells obtained from infected mice previously treated with normal rabbit serum and that of cells from uninfected mice. These data suggest a role for TNF in resistance to N. brasiliensis infection.

Mass spectrometric analysis of O-peracetylated derivatives of 1-monomycoloylglycerol isolated from Corynebacterium pseudotuberculosis, Rhodococcus rhodochrous and R. lentifragmentus

1-Monomycoloylglycerols from Corynebacterium pseudotuberculosis, Rhodococcus rhodochrous and R. lentifragmentus were reacted with acetic acid ahydride in the presence of pyridine. On infrared spectra the reaction products showed a sharp characteristic absorption of the acetyl ester group at 1235 cm-1; the hydroxyl group absorption (3400 cm-1) was absent. O-Peracetylated monomycoloylglycerols were analyzed by mass spectrometry under electron impact mode. The most common and representative peaks were associated to the following remarkable fragments: (a) peak at m/z 159 represented the backbone of the glycerol unit of peracetylated monomycoloylglycerols; it constituted the diagnostic and base peak of that group of compounds; (b) peak representing the glycerol moiety together with the alpha-subunit of the mycolic acid moiety; it gave the size of the chain length of the hydrocarbon side chain of that mycolic acid; and (c) a series of peaks of acylium ions minus 60 mass units (acetic acid) indicated the size of the chain length of the esterified mycolic acid. Therefore, acetylation of monomycoloylglycerol becomes the derivatized compound suitable for mass spectrometry. Moreover, the derivatives are more thermostable and resistant to pyrolysis. By associating these properties, separation and identification of homologs of monomycoloylglycerols are further expected.

Effect of low mole fraction of trehalose dicorynomycolate from Corynebacterium diphtheriae on water permeability and electrical capacitance of lipid bilayer membranes

The effect of incorporation of different proportions of trehalose dicorynomycolates (TDC) into lecithin bilayer membranes was studied. It was found that TDC, induces a 14% decrease of water osmotic permeability (42.6 +/- 3.9 to 36.8 +/- 2.7 microns/s) at 1.6 mole%, suggesting that this substance leads to an increase of the degree of packing of the constituent lipid molecules. A condensing effect of TDC was also apparent from membrane electrical capacitance (Cm) measurement. By incorporating TDC into bilayer membranes, the value of Cm experienced a decrease of 29% at 1.6% mole fraction. This finding was taken to reflect an increase in membrane thickness, known in many examples, to be related to the condensing effect.

Tumor necrosis factor (cachectin) mediates induction of cachexia by cord factor from mycobacteria

The mechanism by which cord factor (CF), a toxic glycolipid from mycobacteria, induces cachexia was studied in BALB/c mice. Body weight was markedly reduced 48 h after CF administration; the animals became severely wasted and exhibited hypertriglyceridemia, hypoglycemia, and high levels of tumor necrosis factor (TNF) in plasma. After CF administration, a transferable factor which caused cachexia and hypertriglyceridemia in recipient mice was detected in the blood. Dexamethasone partially inhibited the cachexia-inducing action of CF. Conditioned medium from adherent peritoneal cell cultures incubated with CF produced the same wasting symptoms when inoculated intravenously into mice. These studies also demonstrated that adherent peritoneal cells produced a humoral factor in response to CF which was related to CF-induced cachexia. Antiserum to recombinant TNF-alpha prevented the cachectin action in passive-transfer experiments. Our findings indicate that cachectin (TNF) plays a role as a central mediator of the wasting induced by CF.

Studies on components of the chloroform-methanol extract from Madurella grisea

Some of the lipids described in many fungi were found in Madurella grisea, in addition to other diethyl ether-soluble components with peculiar characteristics. One fraction structurally related to ethane diol (ethylene glycol) accounted for about 41% and a compound identified as methyl terephthalate represented about 38% of the extract. No steroids were detected. The absence of these lipids may perhaps explain the resistance of this organism to polyene antibiotics.

Glycolipids from Nocardia rhodochrous grown on glucose

Nocardia rhodochrous grown on glucose-supplemented medium produced a high yield of a glycolipid fraction (m.p. 65-70 degrees C and [alpha]25D = + 31.4 degrees), identified as 6-(C40-C46) nocardomycoloylglucose. It accounted for approx. 3.4% of the cell dry wt. and 41% of the diethyl ether soluble lipids obtained from ethanol-diethyl ether extract. Dimycoloyltrehalose (cord factor) was found in a very small amount (0.11%).

Purification of 1-monoacylglycerols containing alpha-branched-beta-hydroxylated fatty acids from lipids of Corynebacterium pseudotuberculosis

A complex mixture of monoacylglycerols, identified as (C30--C36) corynomycoloylglycerols was isolated from the diethyl ether/acetone-soluble lipids of Corynebacterium pseudotuberculosis.