Georg Keleti

Endotoxins, algae and Limulus amoebocyte lysate test in drinking water

Abstract Field and laboratory studies were conducted to determine the distribution of algae and bacteria, and investigate sources of endotoxins (lipopolysaccharides) in drinking water. The field survey was performed on five drinking water systems located in Allegheny County, Pennsylvania during the spring and summer of 1978. The highest concentrations of phytoplankton were found in uncovered finished water reservoirs. The major source of “endotoxic” response as measured by the Limulus amoebocyte lysate (LAL) gelation test was a non-specific reaction caused by algae. This was documented by a highly positive correlation of phytoplankton concentrations occurring in the reservoirs with respective LAL titers. Chlorella vulgaris (Chlorophyta) was the most common alga, whereas Schizothrix calcicola was the most dominant Cyanobacterium found in the five water systems. LAL gelation test with C. vulgaris grown in the laboratory verified the phenomenon observed on samples collected in the field and indicated a non-specific reaction, whereas S. calcicola cultures under identical conditions produced a specific response. Alkali and lysozyme treatments were successful in distinguishing specific and non-specific LAL reactions. These two techniques in conjunction with LAL test are recommended for drinking water quality assessment.

Cyanobacteria and Endotoxins in Drinking Water Supplies

Field and laboratory studies were performed to evaluate the quantitative distribution and sources of endotoxins (lipopoly- saccharides = LPS) in drinking water supplies. The Limulus amoebocyte lysate (LAL) test was used to measure total, bound and free endotoxins in six drinking water systems.

Isolation and Characterization of Endotoxin from Cyanobacteria (Blue-Green Algae)

A Sewickley, Pennsylvania, epidemic of water-borne gastroenteritis of unknown etiology which occurred in 1975 was characterized by high concentration of Schizothrix calcicola (Cyanobacteria) in the corresponding drinking water system. As a consequence, the most common cyanobacterial contaminants of drinking water were tested for endotoxin (lipopolysaccharide - LPS) content. LPS was isolated and characterized from Schizothrix calcicola, Anabaena flos-aquae (UTEX 1444), Oscillatoria tenuis, and Oscillatoria brevis. The isolation was performed by using Westphal’s modified phenol-water extraction method. Subsequently, the glucan contaminating LPS was eliminated by enzymatic hydrolysis by cellulase. The resulting macromolecular substances were composed of a polysaccharide moiety and a lipid part. Contrary to Wang and Hill’s report that Anabaena flos-aquae A37 contains a polysaccharide without covalently bound lipid, Anabaena flos-aquae (UTEX 1444) contained a true LPS. No endotoxin could be isolated from the toxic strain Anabaena flos-aquae NRC-44-1 and preliminarily from Anabaena cylindrica.

Notes. Mutagenicity of SRC-II coal liquefaction wastewater treatment residues

A first screen bioassay of an SRC-II coal liquefaction residue and 3 sludges resulting from treatment of the wastewater from the process was conducted using the Ames test method for detecting mutagenic activity. All of the residues exhibited some mutagenicity, with the vacuum bottom having 700 times greater specific mutagenic activity than fresh clarifier sludge and 5600 times greater mutagenic activity than aged digester sludge in the first sample set. Organic fractions of each of the tested materials, produced by increasing polar solvent extraction, were also measured for mutagenicity. The toluene and hexane fractions of clarifier sludge as compared to digested sludge, which contains the bulk of the polycyclic aromatic hydrocarbons showed little or no reduction in mutagenic activity. The other organic fractions showed great reduction in activity, and in some cases complete elimination of the mutagenic fractions when the sludge has been digested.

Amoebae as sources of hypersensitivity pneumonitis

Abstract Pulmonary hypersensitivity has been associated with inhalation of many diverse occupational and environmental airborne agents. Of biological materials, spores of thermophilic actinomycetes have been recognized frequently as causative agents of the disease. Amoebae have rarely been associated with inhalation hypersensitivity. However, recent isolation of several species of amoebae from heated humidification systems in homes and factories has prompted concern for the role of amoebae in hypersensitivity pneumonitis. In this study, an animal model was employed to investigate hypersensitivity to nonpathogenic Naegleria gruberi . Guinea pigs were sensitized by injection of axenic as well as nonaxenic N. gruberi emulsified in Freunds complete adjuvant. Animals were evaluated for three distinguishing characteristics of hypersensitivity pneumonitis. Delayed-onset skin reactivity was apparent in all animals upon intradermal challenge with N. gruberi antigen. Test sites on animals sensitized with axenic N. gruberi developed extensive rashes lasting 96 h. Antibodies were detected in experimental animals. However, antibodies in animals sensitized with nonaxenic N. gruberi were directed mainly toward the bacteria Enterobacter aerogenes , which was used as the feeder culture. This finding points out the importance of using axenic cultures of amoebae. Bronchial provocation challenge was employed to investigate pulmonary hypersensitivity. Animals sensitized with axenic N. gruberi displayed delayed-onset respiratory responses beginning 6 h post challenge. The study indicates that attention should be given to nonpathogenic free living amoebae as causative agents of hypersensitivity pneumonitis.