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

A chemically defined liquid medium has been developed for the study of the physiology and antigen production of the Legionnaires disease bacterium. The medium contains basal salts, vitamins, alpha-ketoglutaric acid, pyruvate, 0.05% l-cysteine, 0.05% glutathione, and a mixture of 20 additional amino acids, each of 0.01% final concentration, except serine, which was at 0.1%. The medium in shake culture at 37 degrees C with increased CO2 at pH 6.5, supports the maximum rate of growth, the highest cell yields, and the maximum cell surface antigen as distinguished by specific fluorescein isothiocyanate-conjugated antibody. Studies during the development of this medium showed that CO2, pyruvate, and alpha-ketoglutarate strongly stimulated growth; that cysteine and methionine were required for growth; and that serine, threonine, histidine, tyrosine, and tryptophane were energy sources. Glutathione substituted for cysteine, but cystine did not. The organisms did not use glucose and polysaccharides, as judged by cell yields when these carbohydrates were present or absent. The chelators malate, citrate, and ethylenediaminetetraacetic acid totally inhibited growth. Beta-mercaptoethanol, thioglycolate, dithiothreitol, and Tween 80 (0.05%) inhibited growth strongly or completely. Catalase activity was extremely weak or absent. Morphology varied, depending upon conditions and phases of growth. In general, filamentous forms became chains of cigar-shaped bacilli fragmenting to pairs and becoming coccoidal in the late stationary pha-e of growth. The organism grew at 25, 30, and 37 degrees C. Although they varied in their growth characteristics, 10 isolates were passed for five transfers in the chemically defined broth, giving maximum rates of growth, cell yields, and antigen production.
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PMID:Development of a chemically defined liquid medium for growth of Legionella pneumophila. 3 86

The results of serologic, cultural, and DNA relatedness studies have shown that the Legionnaires' disease (LD) bacterium and an unclassified agent isolated in 1947 are the same species. Both organisms grew on charcoal-yeast extract agar, enriched Mueller-Hinton agar, and F-G agar, but neither grew on blood agar, trypticase soy agar, or in thioglycollate broth. Both agents reacted with convalescent sera from patients with Legionnaires' disease and convalescent sera from guinea pigs infected experimentally with the LD bacterium. The percentage of guanine plus cytosine in DNA preparations from each organism was ascertained by thermal denaturation to be 39%. In DNA hybridization reactions the 1947 isolate showed the same degree of relatedness to Philadelphia 1 strain of the LD bacterium as did three recent isolates of the bacterium. The LD bacterium was also shown to be antigenically related to another unclassified organism isolated in 1959.
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PMID:Legionnaires' disease bacterium isolated in 1947. 37 48

A chemically defined medium containing 21 amino acids and inorganic salts was developed which supported the growth of four isolates of Legionnaires disease bacterium (Legionella pneumophila). Growth in liquid defined medium at 37 degrees C with shaking approximated the generation time and growth kinetics observed for growth in complex media. After a 3-h lag, the culture grew exponentially with a generation time of 6 h and reached a maximum optical density of 230 Klett units (170 Klett units corrected for pigment). A soluble brown pigment was first observed as the culture entered late exponential to early stationary phase of growth. Morphologically, L. pneumophila grew in the liquid defined medium with extensive filamentation and numerous intracellular lipid granuoles. L-Serine, L-methionine, and L-cysteine were required for optimum growth. The latter amino acid could be replaced by L-cystine or reduced glutathione but not by D-cysteine, thiomalate, thioglycollate, or 2-mercaptoethanol. Ferric iron was needed for maximum growth, but supplemental iron was not an essential growth requirement. Carbohydrates (i.e., glucose) or organic acids did not stimulate growth. In fact, pyruvate, acetate, and citrate all gave varying degrees of inhibition (69, 37, and 0% of control growth, respectively).
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PMID:Growth of Legionnaires disease bacterium (Legionella pneumophila) in chemically defined medium. 50 Jul 95

The mechanism of the effects of lipopolysaccharide (LPS) on macrophages in terms of replication of intracellular facultative bacteria is unclear. It was found in the present study that the anti-Legionella pneumophila activity induced by LPS in macrophages from susceptible A/J mice was reversed in vitro by dibutyryl cyclic AMP (DcAMP). A 24-h pretreatment of murine thioglycolate-elicited macrophages with LPS resulted in an enhanced ability of these cells to inhibit the intracellular growth of L. pneumophila. This anti-L. pneumophila activity of macrophages induced by LPS was inhibited when DcAMP (10(-3) to 10(-5) M) was present during preincubation with LPS. The addition of DcAMP to the cultures was more effective before LPS treatment than after treatment. The effect of DcAMP was dose dependent. The secretion and production of acid phosphatase by LPS-activated macrophages were also inhibited by the addition of DcAMP before LPS treatment. Furthermore, the anti-L. pneumophila activity of macrophages induced by LPS could also be reversed in vitro by treatment with prostaglandin E2, colchicine, isoproterenol, theophylline, or hydrocortisone, all of which are known to increase the intracellular levels of cyclic AMP in various tissues. These observations indicate that the anti-L. pneumophila activity induced by LPS treatment can be modified by mechanisms involving cyclic nucleotide metabolism.
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PMID:Cyclic AMP inhibition of lipopolysaccharide-induced restriction of Legionella pneumophila growth in macrophage cultures. 131 22

Legionella pneumophila readily grows in cultures of thioglycollate (TGC)-induced macrophages (MPs) from A/J mice, but not in MPs from BALB/c mice or other mouse strains. In the present study, the growth of Legionella pneumophilia in MPs from A/J and BALB/c mice, as well as hybrids of the two strains and back-crossed mice, was investigated to determine whether the permissiveness of growth of these bacteria was due to an inherited trait of the MPs. The MPs from all A/J mice supported the growth of Legionella, regardless of whether they were obtained from TGC or casein injected donors, but the cells from the mice given TGC supported growth of L. pneumophila much better than cells from mice injected with casein. Furthermore, MPs obtained from all BALB/c mice treated with either TGC or casein were nonpermissive for the growth of L. pneumophila. MPs from approximately 46% of the back-crossed ACF1 to A/J mice were permissive for L. pneumophila growth, while MPs from all ACF1 to back-crossed BALB/c mice were found to be nonpermissive. MPs from approximately 19% of ACF2 mice were permissive for L. pneumophila. Killing activities of MPs using temperature sensitive mutants of Salmonella typhimurium were variable and did not correlate with permissiveness or nonpermissiveness for growth of L. pneumophila.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Genetic control of macrophage susceptibility to infection by Legionella pneumophila. 157 91

Similar to guinea pig macrophages and human monocytes, macrophages from the peritoneal cavity of thioglycolate pretreated A/J mice are permissive for growth of Legionella pneumophila. In contrast, macrophages from BDF1 mice are not permissive for L. pneumophila. Lymphocytes from A/J and BDF1 mice proliferated in response to Legionella Ag but guinea pig lymphocytes did not. Also, splenocyte cultures from A/J mice treated with either Con A or Legionella vaccine produced supernatants which induced A/J macrophages to restrict Legionella growth, but guinea pig splenocyte culture supernatants obtained after stimulation with L. pneumophila vaccine did not induce Legionella growth restriction activity by guinea pig macrophages. Murine rIFN-gamma but not rIFN-alpha markedly inhibited growth of Legionella in A/J mouse macrophages and monoclonal anti-IFN-gamma antibody neutralized the anti-Legionella activity of culture supernatants from A/J mouse splenocytes responding to Legionella Ag. From these data, IFN-gamma appears to be an important factor in anti-Legionella activity of Ag-activated mouse splenocyte culture supernatants. Cyclosporin A, when given to either A/J or BDF1 mice, reduced the proliferation responses of splenocytes to T cell mitogens and also decreased the IFN production of A/J spleen cells to Legionella Ag. In addition, drug treatment decreased the resistance of A/J mice to Legionella infection as shown by an increase in the number of viable bacteria in the liver. However, injection of drug treated mice with lymphokine-rich splenocyte culture supernatant reconstituted the resistance of these animals. These results suggest an important role for lymphocyte activation and lymphokine production in the resistance of A/J mice to Legionella infection. The greater resistance of BDF1 mice, however, may result from nonpermissive macrophages and responsive lymphocytes. In the case of guinea pigs, susceptibility to Legionella infections may result from both the permissive nature of the macrophages and the relatively unresponsive nature of the lymphocytes in these animals.
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PMID:Differing macrophage and lymphocyte roles in resistance to Legionella pneumophila infection. 172 75

Legionella pneumophila (Lp) grow in cultures in human, guinea pig, and mouse macrophages from A/J strain mice. Because exudate macrophages from this strain of mice have been reported deficient in responsiveness to lymphokines, we thought it of interest to document the extent of responsiveness to interferon-gamma in the context of growth restriction of Lp. Peritoneal exudate macrophages were obtained from A/J mice and cultured in either the presence or absence of recombinant interferon-gamma. These cultures were then infected with Lp and the extent of bacterial growth estimated 48 hr later by means of a colony-forming unit (CFU) assay and electron microscopy. Interferon-gamma treatment significantly restricted the number of CFUs in the culture at concentrations as low as 20 U/ml, but did not affect the uptake of bacteria by macrophages. Furthermore, treatment with interferon induced morphological changes consistent with activated macrophages. The involvement of oxygen-dependent mechanisms in phagocyte killing and growth restriction was examined by the use of inhibitors such as superoxide dismutase (SOD) and catalase. Neither one of these inhibitors of toxic oxygen metabolites affected the interferon-gamma-induced suppression of Lp growth. These results suggest that although thioglycolate-induced exudate macrophages from A/J mice support the growth of Lp, these cells readily respond to the activating influence of interferon-gamma. Furthermore, lymphokine treatment does not inhibit Lp uptake by macrophages and apparently restricts the growth of bacteria by mechanisms independent of the activity of toxic oxygen metabolites.
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PMID:Interferon-gamma induced resistance to Legionella pneumophila in susceptible A/J mouse macrophages. 189 14

It is known that Legionella pneumophila proliferates in peritoneal macrophage cultures derived from A/J mice but not in macrophage cultures derived from many other strains, including C57BL/6 mice. To analyze the genetic control of this trait and the location of the Legionella resistance-susceptibility gene, we prepared segregating progeny of A/J and C57BL/6 mice and determined the levels of susceptibility of individual mice. Peritoneal macrophages were collected by injecting thioglycolate medium, and macrophage monolayers were infected in vitro with L. pneumophila Philadelphia-1. Counting of colonies on buffered charcoal yeast extract agar plates and Gimenez staining of macrophage monolayers were carried out daily. There was a 10-fold increase in bacterial burden 1 day after infection and a 100-fold increase after 2 days in A/J (susceptible) macrophages. The increase in bacterial burden was always less than 10-fold in macrophages from C57BL/6 (resistant) progenitors, A/J x C57BL/6 F1 hybrids, and C57BL/6 x F1 backcross progeny. The ratios of resistant individuals to susceptible individuals were 22:6 for F2 progeny and 20:22 for A/J x F1 backcross progeny. The fact that the organism did not proliferate in macrophages from B10.A mice demonstrated that major histocompatibility antigens did not regulate the macrophage resistance of C57BL/6-derived mice. The sex and coat color genes of mice were not linked to the resistance-susceptibility gene. We suggest that resistance and susceptibility are controlled by a single gene or closely linked genes which are autosomal and that the resistance allele is dominant. The results of a comparison of the strain distribution pattern of this trait with the distribution pattern of 185 allelic markers in A/J x C57BL/6 and C57BL/6 x A/J recombinant inbred strains suggest that this susceptibility-resistance gene is located in the proximal part of chromosome 15.
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PMID:Genetic control of natural resistance in mouse macrophages regulating intracellular Legionella pneumophila multiplication in vitro. 198 55

Tumor necrosis factor (TNF) was found in the lung lavage fluids of Legionella pneumophila-infected mice within 24 hr of intratracheal (i.t.) inoculation. Since this cytokine has been reported to activate polymorphonuclear leukocyte (PMN) function, the effect of TNF on the in vitro bactericidal capacity of PMN-enriched cultures was determined. Murine thioglycollate-elicited PMN which were treated with recombinant human TNF demonstrated augmented killing of L. pneumophila bacteria in vitro. Furthermore, treatment of PMN suspensions with cytokine-containing lung lavage fluid was found to enhance the bactericidal activity of PMN. The addition of anti-cachectin/TNF antibodies partially abrogated the stimulatory effects of the lavage fluid, suggesting that in vivo activation of PMN during the course of infection was likely, and that TNF was partially responsible for the enhanced bactericidal activity. In vivo treatment of animals with TNF resulted in significant protection of the animals from mortality. Furthermore, the rate of clearance of bacteria from the lung tissues of infected mice was increased in those animals treated with TNF, and correlated with the ability of this cytokine to protect the animals. These data suggest that the induction of TNF by Legionella bacteria during infection are involved in the non-specific host defense mechanisms, and that PMN activated by the TNF may be instrumental in clearing the organism from infected lung tissues, thereby protecting the animal.
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PMID:Protective effects of tumor necrosis factor in experimental Legionella pneumophila infections of mice via activation of PMN function. 316 17

Legionella pneumophila is a facultative intracellular bacterium which readily grows in cultures of guinea pig and human mononuclear phagocytes. In this report, we demonstrate that the Legionella sp. also grows in thioglycolate-elicited macrophages obtained from A/J mice but not in cells from other mouse strains tested, such as BDF1, DBA/2, C3H/HeN, C57BL/6, and BALB/c. Growth of Listeria monocytogenes and interleukin-1 production in A/J mice were similar to their growth and production in other strains tested, and the growth of Staphylococcus epidermidis was restricted by A/J macrophages. This finding suggests that although A/J macrophages share functional capabilities with cells from other mouse strains, they differ in growth restriction capacity for the Legionella sp. Resident macrophages were less permissive than were thioglycolate-elicited cells in that resident cells from A/J mice failed to support the growth of Legionella pneumophila. Also, resident cells from BDF1 mice rapidly eliminated the bacteria, rather than merely restricting growth. This finding was also observed in in vivo studies in which thioglycolate pretreatment of mice resulted in the enhanced recovery of viable bacteria from the peritoneal cavity of mice infected intraperitoneally. Higher numbers of bacteria were obtained from A/J mice and, in addition, this strain was more susceptible to the lethal effects of Legionella infection. These data suggest that, as with other intracellular bacteria, macrophages may serve a pivotal role in the early stages of Legionella infection and further suggest that the A/J mouse represents a useful animal model for the study of Legionella infection and immunity.
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PMID:Growth of Legionella pneumophila in thioglycolate-elicited peritoneal macrophages from A/J mice. 325 60


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