The effect of fatty acids on the respiration of Leptospira icterohemorrhagiae

NUTRITION OF LEPTOSPIRA POMONA. II. FATTY ACID REQUIREMENTS

Johnson, R. C. (Fort Detrick, Frederick, Md.) and N. D. Gary. Nutrition of Leptospira pomona. II. Fatty acid requirements. J. Bacteriol. 85:976-982. 1963.-The albumin fraction of rabbit serum, obtained by (NH(4))(2)SO(4) fractionation, supported good growth of Leptospira pomona Wickard when added to a medium containing phosphate buffer, NH(4)Cl, and thiamine. Extraction of the albumin fraction with ethanol and ether (3:1) resulted in a loss of its growth-supporting activity, which could be restored upon the addition of the extract or various fatty acids. The growth-supporting activity of fatty acids containing 2 to 18 carbon atoms was investigated with the extracted albumin medium. The activity of the fatty acid was found to be related to the number of carbon atoms in the molecule. Maximal growth was obtained with palmitic, heptadecanoic, stearic, and oleic acids. The amount of growth of L. pomona increased at a fixed concentration of albumin as the molecular ratio of extracted albumin to the long-chain fatty acids increased from 1:1 to 1:6. At higher ratios, growth decreased sharply. Direct utilization of fatty acids during growth of L. pomona was shown by the incorporation of palmitic acid-1-C(14) or -2-C(14) into cellular material. A medium composed of 0.02 m Na(2)HPO(4)-KH(2)PO(4) buffer (pH 7.4), 0.8% extracted albumin, 4 x 10(-4)m palmitic acid, 10(-3)m NH(4)Cl, and 5 mug/ml of thiamine supported good growth. L. pomona was transferred ten times, and seven other serotypes were transferred five times, in this medium without any decrease in the amount of growth. Growth of L. pomona was initiated with approximately four organisms per ml.

CATALASE ACTIVITY IN LEPTOSPIRA

Rao, P. J. (University of Illinois, Urbana), A. D. Larson, and C. D. Cox. Catalase activity in Leptospira. J. Bacteriol. 88:1045-1048. 1964.-A number of serotypes of Leptospira were found to possess catalase activity, although considerable variation in activity existed among various serotypes. Catalase activity of L. pomona was reduced by inhibitors commonly employed for arresting catalase activity in other biological systems. Catalase activity was increased three to five times by growing cultures under conditions of oxygen availability; however, aeration had no beneficial effect on total viable cell crop. The relationship of oxygen to metabolism and future studies on virulence of the leptospirae is discussed.

Phospholipid catabolism enzymes of leptospires

Phospholipase A2, C, D activities of pathogenic (VGNCI-3, HS-26) and saprophytic (K-1028, G-80) strains of leptospires were determined. The strains used synthesized intracellular and extracellular forms of these esterases. To a considerable degree the endophospholipase activity was associated with the membrane structures. Differences in substrate specificity, Km, Vmax pH optimum values between exophospholipases of pathogenic and saprophytic leptospires used in the experiments are demonstrated.

Fatty acid profiles in the family Leptospiraceae

Fatty acid profiles of six leptospira strains representative of genera, species, and serogroups within the family Leptospiraceae were determined by gas liquid chromatography (GLC) of fatty acid methyl ester (FAME) derivatives. The influence of methodological and biological variables on FAME profiles of the same strain was tested. FAME profiles were sharply affected by the fatty acid composition of the culture medium but not by the growth phase. Twenty-four FAME peaks were selected on the basis of their presence in repeated gas chromatographic runs of single strains. Inter-strain divergences of FAME profiles were quantified by linear regression analysis (LR). Step-wise divergences in FAME profiles were observed between strains at serogroup, species, and genus levels.

Composition of fatty acids and carbohydrates in Leptospira

The fatty acid and monosaccharide composition of four pathogenic and two saprophytic strains of Leptospira was analyzed by gas chromatography (GC) and GC-mass spectrometry. Among the fatty acids, palmitic acid was most abundant and constituted 30 to 50% of the total fatty acids. Even-numbered unsaturated acids including octadecenoic, hexadecenoic, octadecadienoic, and tetradecadienoic acids comprised 40 to 60% of the total fatty acids. Tetradecanoic acid was about 5% in saprophytic strains, but 1% or less in pathogenic strains. The amount of chloroform-methanol extract of L. biflexa strain Ancona was 14 to 20% of the dry weight of the cell. Tetradecadienoic acid was found in the chloroform-methanol insoluble fraction, suggesting the presence of the acid in a bound form. GC analysis of monosaccharides revealed the existence of arabinose, xylose, rhamnose, mannose, galactose, glucose, glucosamine, and muramic acid in the cells. Among the neutral sugars, glucose was a minor component and was especially low in pathogenic strains. Total pentose content was about two to three times greater than total hexose.

Effect of isomeric cis-octadecenoic acids on the growth of Leptospira interrogans serotype patoc

Leptospira interrogans serotype patoc exhibited an increasing growth response when cultivated in media containing from 50 to 250 mug of sodium oleate per ml. Leptospiral growth in the presence of 250 mug of sodium oleate per ml was as good as that in the basal medium which contained 700 mug of oleic acid (in Tween 80) per ml. When positional isomers of oleic acid (9-octadecenoic acid) were present at a concentration of 200 mug/ml, the 2- and 8-isomers were not readily utilized, whereas the 3-, 4-, 6-, 11-, 15-, and 16-isomers gave a growth response equivalent to that of oleic acid, i.e., the 9-isomer. The 5-, 7-, 10-, 12-, 13-, 14-, and 17-isomers of octadecenoic acid induced growth responses which differed in magnitude but were intermediate to those of 2-18:1 and 3-18:1. When 200 mug of either 2- or 3-octadecenoic acid per ml was added in addition to 200 mug of 9-18:1 alone; 400 mug of 9-18:1 alone per ml inhibited growth of this organism. The growth response of leptospira to octadecenoic acids differed from that of mammalian cells, suggesting the presence of different enzymes in the two systems for the utilization of these substrates.

Intermediate energy metabolism of Leptospira

Metabolic studies were performed on three representative serotypes of Leptospira: a water isolate designated B(16) and two pathogenic serotypes, pomona and schueffneri. Examination of whole cells of B(16) for their ability to oxidize various substrates revealed that oleate significantly stimulated oxygen uptake. The respiratory quotient of 0.7 implied that oleate was degraded to carbon dioxide and water. Other substrates, such as carbohydrates, alcohols, intermediates of the citric acid cycle, and short-chain acids, including selected amino acids, did not stimulate endogenous respiration of whole cells. No oxygen uptake could be measured when cell-free extracts were tested with the substrates used with whole cells. Enzymatic analyses of cell-free extracts of the three strains demonstrated enzymes of the citric acid cycle, enzymes of the glycolytic and pentose pathways, and the general acyl coenzyme A dehydrogenase required for beta-oxidation of fatty acids. Strain B(16) and the two pathogenic serotypes appeared to possess similar metabolic capabilities. Enzymatic data might also explain the apparent inability of B(16) to oxidize other substrates; kinases necessary for activation of common nonphosphorylated compounds were not detected in leptospiral extracts. These findings emphasized the dependence of leptospiral growth upon long-chain fatty acids.

Growth of pathogenic Leptospira in chemically defined media

A protein-free chemically defined medium for cultivation of pathogenic Leptospira was developed. The medium permitted continued serial subculturing of 9 serogroups (52 strains) of the 12 serogroups (61 strains) tested. Growth was initiated from small inocula, and the growth rate and maximal cell yields were similar to those on serum-containing media. The nutritional requirements of serogroups L. canicola, L. pomona, and L. grippotyphosa were studied in a basal medium composed of inorganic salts, a fatty acid, vitamin B(12), and thiamine. All strains tested utilized ammonium chloride as the sole nitrogen source. A fatty acid, vitamin B(12), and ferrous ions were essential. Growth was stimulated by thiamine, potassium, and calcium ions.