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Query: UMLS:C0023241 (Legionella)
 6,990 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Keto acids and reduced-oxygen-scavenging enzymes were examined for their roles in supporting the growth of Legionella species and for their potential reactions between the chemical components of the media. When grown in an experimental ACES (2-[(2-amino-2-oxoethyl)-amino] ethanesulfonic acid)-buffered chemically defined (ABCD) broth, the presence of keto acids shortened the lag periods, increased the rates of growth, and gave maximum cell yields. In addition, keto acids affected the specific activities of reduced-oxygen-scavenging enzymes determined during growth. The specific activities of superoxide dismutase of Legionella pneumophila (Knoxville) and L. dumoffii (TEX-KL) were increased three- to eightfold, while that of L. bozemanii (WIGA) was not affected. All strains appeared to be equally sensitive to the effects of superoxide anion (O2-) generated by light-activated riboflavin, and all were equally protected by the presence of keto acids in the ABCD broth. Production of trace amounts of acetate and succinate in pyruvate- and alpha-ketoglutarate-containing media exposed to light suggested that hydrogen peroxide was formed. Pyruvate and alpha-ketoglutarate were products of growth on amino acids, and there was no quantitative evidence that these keto acids were metabolized when they were added to the medium. The rate of cysteine oxidation in ABCD broth was increased by the presence of ferric ion or by exposure to light or by both, and keto acids reduced the rate of this oxidation. ACES buffer was a substrate for the production of O2- in the presence of light, and the combined addition of Fe2+ ions, cysteine, and either keto acid to the medium strongly inhibited the production of O2-. Thus, keto acids inhibited the rate of cysteine oxidation, they stimulated rapid growth by an unknown process, and, in combination with added Fe2+ ions and cysteine, they reversed the toxic effects of light by inhibiting O2- production.
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PMID:Role of keto acids and reduced-oxygen-scavenging enzymes in the growth of Legionella species. 300 29

The growth in liquid media of Legionella pneumophila serogroups 1-6 was monitored turbidimetrically and factors affecting growth rate were studied. The presence of inhibitors, use of detoxifying agents and the method of broth preparation each had significant effects on cultivation. Cysteine was essential for growth; the optimal concentration was 100 micrograms/ml, but supplemental iron had no demonstrable effect.
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PMID:Factors affecting growth of Legionella pneumophila in liquid media. 301 52

Two Legionella-like organisms were isolated from cooling-tower water samples in Czechoslovakia. They were presumptively identified as legionellae by their growth on buffered charcoal-yeast extract agar (BCYE) containing L-cysteine and their absence of growth on BCYE without L-cysteine. Both strains contained predominately branch-chained cellular fatty acids and were therefore definitively placed in the genus Legionella. They were serologically distinct from other described Legionella species and were shown by DNA studies to constitute two new Legionella species, Legionella moravica (type strain 316-36; ATCC 43877) and Legionella brunensis (type strain 441-1; ATCC 43878).
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PMID:Legionella moravica sp. nov. and Legionella brunensis sp. nov. isolated from cooling-tower water. 317 63

A Legionella-like organism, strain 1407-AL-H, was isolated from a transbronchial lung biopsy specimen from a cardiac transplant recipient undergoing immunosuppressive therapy. The strain grew on buffered charcoal-yeast extract agar (BCYE) but not on BCYE in the absence of cysteine, and it showed gas-liquid chromatographic fatty acid profiles that were predominantly branch chained. Strain 1407-AL-H was antigenically distinct in slide agglutination tests from the 23 Legionella species and 39 serogroups previously described. DNA hybridization studies placed it in a new Legionella species, Legionella birminghamensis (ATCC 43702).
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PMID:Legionella birminghamensis sp. nov. isolated from a cardiac transplant recipient. 332 81

Legionella pneumophila and related species were examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis for outer membrane proteins. Of the 10 species examined, 9 contained a 24-kilodalton (kDa) major outer membrane protein (MOMP) that was resolvable only when outer membrane material was heated in the presence of 2-mercaptoethanol. Labeling studies with [35S]cysteine indicated that the protein contained cysteine, and disulfide cross-linking of the unreduced complex was demonstrated by labeling with iodoacetamide. The unreduced outer membrane preparation contained peptidoglycan, and after treatment with lysozyme to remove peptidoglycan, a protein complex of 95 kDa was observed by sodium dodecyl sulfate polyacrylamide gel electrophoresis in the absence of 2-mercaptoethanol. Reduction of the 95-kDa complex yielded 24-kDa monomers, suggesting that the 95-kDa complex was composed of four subunits. The 24-kDa MOMP from L. pneumophila was purified, and antibody produced to this protein cross-reacted with all species of Legionella as determined from an immunoblot of a sodium dodecyl sulfate gel. Only serogroup 1 strains of L. bozemanii lacked the 24-kDa MOMP and showed no cross-reactivity. These results suggest that the 24-kDa MOMP common to most species of Legionella contains a genus-specific epitope.
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PMID:Disulfide-bonded outer membrane proteins in the genus Legionella. 398 79

Between March 1980 and June 1981, five strains of Legionella-like organisms were isolated from water. Four were recovered from potable water collected from hospitals in Chicago, Ill., and Los Angeles, Calif., during outbreaks of nosocomial legionellosis. The fifth strain was isolated from water collected from an industrial cooling tower in Jamestown, N.Y. The strains exhibited biochemical reactions typical of Legionella species and were gram-negative motile rods which grew on buffered charcoal-yeast extract agar but not on blood agar, required cysteine, and were catalase positive, urease negative, nitrate negative, hippurate negative, and nonfermentative. All strains were positive for oxidase and beta-lactamase and produced a brown, diffusible pigment. Of the five strains, four exhibited blue-white autofluorescence under long-wavelength UV light. The fatty-acid composition and ubiquinone content of these strains were consistent with those of other Legionella species. Direct fluorescent-antibody examination of the five strains with conjugates to previously described Legionella species demonstrated no cross-reactions except with the conjugates to L. longbeachae serogroup 2 and L. bozemanii serogroup 2. Four strains gave a 4+ reaction to the L. longbeachae serogroup 2 conjugate and the fifth strain gave a 1+ reaction. Each of the five strains gave a 4+ reaction with the conjugate to L. bozemanii serogroup 2. DNAs from the five strains were highly related (84 to 99%) and showed 5 to 57% relatedness to other Legionella species. These strains constitute a new species in the genus Legionella, and the name Legionella anisa sp. nov. is proposed. The type strain of L. anisa is WA-316-C3 (ATCC 35292).
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PMID:Legionella anisa: a new species of Legionella isolated from potable waters and a cooling tower. 398 9

A naturally occurring suspension of Legionella pneumophila and associated microbiota contained three unidentified non-Legionellaceae bacteria which supported satellite growth of a subculture of L. pneumophila on an L-cysteine-deficient medium and another bacterium which did not support growth of the subculture. Washed suspensions containing 10(3), 10(5), 10(7), or 10(8) CFU of a mixture of isolates of these non-Legionellaceae bacteria failed to support the multiplication of an isolate of agar-grown L. pneumophila which had been washed and seeded into the suspensions. The suspensions which contained 10(3), 10(5), or 10(7) CFU of the non-Legionellaceae bacteria per ml appeared to enhance survival or cryptic growth of agar-grown L. pneumophila. A decline of 1.3 log CFU of L. pneumophila per ml occurred within the first week of incubation in the sample which contained 10(8) CFU of the non-Legionellaceae bacteria per ml. In contrast to these results, naturally occurring L. pneumophila multiplied in the presence of associated microbiota. The necessity to subculture L. pneumophila and the non-Legionellaceae bacteria on artificial medium to obtain pure cultures may have affected the multiplication of L. pneumophila in tap water. Alternatively, other microorganisms may be present in the naturally occurring suspension which support the growth of this bacterium.
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PMID:Effect of non-Legionellaceae bacteria on the multiplication of Legionella pneumophila in potable water. 400 34

The amino acids L-arginine, L-isoleucine, L-leucine, L-methionine, L-serine, L-threonine, and L-valine were essential for the growth of Legionella pneumophila in a chemically defined medium. A partial requirement for L-cysteine (or L-cystine) was also observed. A minimal medium containing only the eight required amino acids supported the growth of this bacterium only if the medium was supplemented with L-glutamic acid. This latter compound was the only amino acid capable of stimulating growth in the eight-amino acid medium.
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PMID:Amino acid requirements for Legionella pneumophila growth. 611 50

A method is described for the presumptive identification of Legionella pneumophila by the formation of satellite colonies around filter paper discs impregnated with ferric pyrophosphate and L-cysteine hydrochloride on a deficient basal medium. This technique simplifies the differentiation of picked colonies of L pneumophila from other organisms in mixed cultures from environmental and contaminated clinical samples.
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PMID:A simple disc technique for the presumptive identification of Legionella pneumophila. 629 45

The difficulties associated with the growth of Legionella species in common laboratory media may be due to the sensitivity of these organisms to low levels of hydrogen peroxide and superoxide radicals. Exposure of yeast extract (YE) broth to fluorescent light generated superoxide radicals (3 microM/h) and hydrogen peroxide (16 microM/h). Autoclaved YE medium was more prone to photochemical oxidation than YE medium sterilized by filtration. Activated charcoals and, to a lesser extent, graphite, but not starch, prevented photochemical oxidation of YE medium, decomposed hydrogen peroxide and superoxide radicals, and prevented light-accelerated autooxidation of cysteine. Also, suspensions of charcoal in phosphate buffer and in charcoal yeast extract medium readily decomposed exogenous peroxide (17 and 23 nmol/ml per min, respectively). Combinations of bovine superoxide dismutase and catalase also decreased the rate of photooxidation of YE medium. Medium protected from light did not accumulate appreciable levels of hydrogen peroxide, and autoclaved YE medium protected from light supported good growth of Legionella micdadei. Various species of Legionella (10(4) cells per ml) exhibited sensitivity to relatively low levels of hydrogen peroxide (26.5 microM) in challenge experiments. The level of hydrogen peroxide that accumulated in YE medium over a period of several hours (greater than 50 microM) was in excess of the level tolerated by Legionella pneumophila, which contained no measurable catalase activity. Strains of L. micdadei, Legionella dumoffi, and Legionella bozmanii contained this enzyme, but the presence of catalase did not appear to confer appreciable tolerance to exogenously generated hydrogen peroxide.
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PMID:Production of superoxide and hydrogen peroxide in medium used to culture Legionella pneumophila: catalytic decomposition by charcoal. 630 19


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