Light and electron microscopic demonstration of phospholipase B activity in the mouse eosinophil.

Phospholipase B (EC 3.1.1.5) which hydrolyzes phospholipids in the alpha and beta positions was demonstrated in murine leukocytes using light and electron microscopic histochemical techniques. Leukocytes (neutrophils, lymphocytes, macrophages, eosinophils) were harvested from peritoneal exudates of mice. Cells were fixed in 4% calcium-formol fixative for 10 min at 4 degrees C for light microscopy and 30 min at room temperature for electron microscopy, after which they were incubated at 37 degrees C in medium at pH 6.6 containing 2 microM lysolecithin and CaCl2. The fatty acids released during the hydrolytic reaction were trapped as a calcium precipitate and were converted to a cobalt precipitate for light microscopy by treatment with cobalt acetate or to a lead precipitate for electron microscopy by treatment with lead nitrate. The reaction products were observed to be present in eosinophils and absent in neutrophils, lymphocytes and macrophages. It is concluded that the eosinophilic leukocyte is the carrier cell for phospholipase B in inflammatory reactions.

Ascaris lumbricoides suum: morphological characterization of apparent cuticular pores by ionic permeability and electron microscopy.

The cuticle of the parasitic roundworm Ascaris lumbricoides suum has been found to contain apparent pores, using scanning and transmission electron microscopy. However, X-ray spectral analysis and dot mapping analysis of diffusing divalent cations in the cuticle found these ions to be randomly distributed on the pseudocoelomic surface of the cuticle. This indicates that the pores seen with the electron microscope were not true structural pores and that the cuticle is homogeneously permeable to ions.

Nutrition of Vitreoscilla stercoraria.

The present study has shown that the glutamate or aspartate families, plus the aromatic amino acid family are required for growth of Vitreoscilla stercoraria. Furthermore, glutamine can substitute for the glutamate family, asparagine and methionine can replace the aspartate family, and tyrosine can substitute for the aromatic family. Amino acids which are easily oxidized by this organism, particularly serine and cysteine, stimulated growth. From these data, a defined medium was devised, which contained the fewest amino acids that could support good growth of V. stercoraria.

Valine, malic, and pyruvic dehydrogenase tests in the differentiation of Bacteroides.

Fifteen isolates of Bacteroides were tested for their ability to dehydrogenate a variety of amino acids and organic acids. A simple and rapid method was developed for detecting dehydrogenase activity using 2,3,5-triphenyl tetrazolium chloride as a hydrogen acceptor and indicator. The results indicate that the tests for valine, malic, and pyruvic acid dehydrogenases have value in differentiating organisms in this genus.

Physiological studies on Vitreoscilla stercoraria.

Vitreoscilla stercoraria ATCC 15218 was studied to elucidate some of its physiological characteristics. The initial optimal pH for the organism was found to be 7.5 to 7.7. The characteristics of the growth curve of the organism showed that its growth in shake cultures is by increasing trichome number up to approximately 15 hr and by increasing trichome length after 15 hr. Nutritional studies indicated that it is auxotrophic for biotin, thiamine, and l-arginine, and it appears to be an obligate amino acid utilizer because only protein hydrolysates or known amino acid mixtures would support growth.