The glucomannan system from Aloe vahombe (liliaceae). III. Comparative studies on the glucomannan components isolated from the leaves.

The polysaccharide mixture obtained by hot water extraction of Aloe vahombe leaves is composed of at least four different paritally acetylated glucomannans which differ in molecular weight, glucose to mannose ratios and acetyl contents. Furthermore, one fraction contains a small but significant amount of protein which could not be removed by gel filtration in a hydrogen-bond-breaking medium, by DEAE-Sephadex A-50 anion exchange chromatography, or by Sevag's method.

Further studies of the glucomannan from Aloe vahombe (liliaceae). II. Partial hydrolyses and NMR 13C studies.

The polysaccharide from Aloe vahombe (lilaceae) was submitted to partial hydrolyses by sulfuric, oxalic and phosphoric acid. Some oligosaccharides were isolated and investigated by chemical and 13C NMR spectroscopic methods. Their structure was determined. The results prove unambiguously that in the analyzed material the D-mannose is linked to the D-glucose by beta-1----4 linkages to form a carbohydrate heteropolymer.

A new enkephalin analogue: trans-4-hydroxycinnamoyl-glycyl-glycyl-phenylalanyl-leucine. Synthesis and biological properties.

A new analogue of the leucine-enkephalin in which the N-terminal tyrosine has been replaced by trans-4-hydroxycinnamic acid, has been synthetized by liquid-phase coupling methods. The central cardiovascular effects of this analogue were investigated and the results discussed.

A 400 MHz 1H NMR study of fortuitin, a natural linear lipopeptide.

Fortuitin is a linear acyl nonapeptide methyl ester in which all the peptide residues are hydrophobic. Its 400 MHz 1H NMR spectrum in pyridine-d5 has been assigned. In this solvent, its conformation is not random and seems to form a hairpin. Conformational equilibria exist in pyridine as well as in less polar solvents such as CDCl3 and CD2Cl2. As for other lipopeptides, conformation and self-association properties strongly depend on the polarity of the environment. These properties should be related to the interactions of lipopeptides with membranes and to their capacity to induce pore formation.

Rapid leucine-enkephalin synthesis.

Leucine-enkephalin, a naturally occurring pentapeptide with morphine-like activity, has been synthesized by a fragment condensation liquid phase method using 1,3,4-trimethyl-delta 3-phospholene-1,1-dichloride as a coupling agent. The advantages of this method are discussed.

Chemical and biological properties of a peptido-glucan fraction from Armillaria mellea (Basidiomycetes).

A peptide-glucan fraction from Armillaria mellea (Basidiomycetes) was isolated and some aspects of its chemical structure were determined. The glucan is linked to the peptide portion which represents 30% w/w of the complex. Treatment with alkali destroys most of the threonine and leads to the separation of the peptide and carbohydrate moieties indicating the involvement of the hydroxyl group of threonine in the peptide-glucan linkage. The results of partial hydrolysis, methylation studies and Smith degradation involving periodate oxidation, borohydride reduction and acid hydrolysis indicate that the polysaccharide moiety consists of beta(1 leads to 3) and beta(1 leads to 6)-linked D-glucose residues. This peptide-rich glucan fraction showed a significant antitumor activity.

Cellular reaction in the footpad and draining lymph nodes of mice induced by mycobacterial fractions and BCG bacilli.

Ten micrograms of trehalose-6, 6'-dimycolate (cord factor), injected into the footpad of mice, induced histological changes similar to those following injection of living BCG bacilli. Both materials induced in the draining lymph nodes the formation of granulomas composed of epitheloid cells, macrophages, and small numbers of lymphocytes. Apart from the granulomatous inflammatory process, marked hyperplasia of the lymphoid tissue in the paracortical zone of the nodes and accumulations of macrophages were evident. In some cases, the macrophages were very numerous and replaced part of the lymphoid tissue. Compared to cord factor, wax D showed weak granulomagenic activity. Only slight and transient inflammation was found in the footpads as well as transient slight lymphoid hyperplasia. Wax D also induced small accumulations of macrophages. Complete Freund's adjuvant induced, under the same experimental conditions, large accumulations of macrophages in the draining lymphnode and lymphoid hyperplasia in the paracortical zone. No cellular reaction was seen in the liver, spleen, and lungs after injection of cord factor and BCG into the footpads of the animals. The results and implications are discussed.

Immune response to sheep red blood cells in mice pretreated with mycobacterial fractions.

Ten micrograms of trehalose-6,6' -dimycolate (cord factor) injected into the footpads of mice increased the antibody response to sheep red blood cells (SRBC) subsequently injected into the same sites. There is a relationship between the antibody response and the cellular reaction induced locally and in the draining lymph nodes by cord factor, as judged by a much weaker response when antigen is injected into the contralateral footpads. The time intervals between injection of cord factor and antigen were from 5 to 20 days. A similar increased antibody response to SRBC was evident after preliminary administration of Freund's complete adjuvant or living BCG bacilli into the footpads. There was no increased antibody response in mice pretreated with living BCG or Freund's adjuvant to SRBC injected into the contralateral footpads. Administration of wax D from human strains Peurois and Test was without any effect. Administration of SRBC emulsified in incomplete Freund's adjuvant containing 5 mug of cord factor induced a very strong antibody response in the mice as compared to that after injection of the same amount of antigen in incomplete Freund's adjuvant containing wax D or mycobacteria. The results are discussed.