ライフサイエンスコーパス: leukotoxin

1 in that is specific for ruminant leukocytes (leukotoxin).

2 sequence similarity with any other bacterial leukotoxin.

3 antiserum raised against the F. necrophorum leukotoxin.

4 mitans has the potential to secrete abundant leukotoxin.

5 method to partially purify large amounts of leukotoxin.

6 ich results in enhanced transcription of the leukotoxin.

7 n the activation and lytic activities of the leukotoxin.

8 ometry with biologically active biotinylated leukotoxin.

9 ctivation of the proleukotoxin to the mature leukotoxin.

10 ca that does not produce biologically active leukotoxin.

11 to be resistant to the lytic effects of the leukotoxin.

12 ost recently described S. aureus bicomponent leukotoxin.

13 ) toxin family related to the M. haemolytica leukotoxin.

14 ocidin (PVL), a well-characterized S. aureus leukotoxin.

15 s and abscess models as those containing the leukotoxin.

16 factors including bi-component pore-forming leukotoxins.

17 ar, S. aureus produces potent hemolysins and leukotoxins.

18 evolutionary histories and encode divergent leukotoxins (5.3% amino acid divergence), but both conta

19 a-hemolysin (HlyA) from Escherichia coli and leukotoxin A (LtxA) from Aggregatibacter actinomycetemco

20 Its major virulence factor is leukotoxin, a high-molecular-weight secreted protein, pr

21 major virulence factor of this bacterium is leukotoxin, a secreted protein of high molecular weight

22 omycetemcomitans defective for production of leukotoxin, a toxin that is reportedly highly specific f

23 n LktAN684K substitution possesses wild-type leukotoxin activity against BL-3 cells and does not acqu

24 lting lktC strain (SH2099) secretes inactive leukotoxin and carries no known antibiotic resistance ge

25 mporal differences in gene expression during leukotoxin and endotoxin activation.

26 s in the regulation of intracellular Ca2+ by leukotoxin and endotoxin are not known.

27 Leukotoxin and endotoxin derived from Pasteurella haemol

28 acrophages, intracellular Ca2+ regulation by leukotoxin and endotoxin was studied by video fluorescen

29 Actinobacillus actinomycetemcomitans leukotoxin and Escherichia coli alpha-hemolysin are RTX

30 sera raised against native affinity-purified leukotoxin and further extension of the sequence using i

31 onditions that modulate transcription of the leukotoxin and lapT promoters.

32 us concentrations of immunoaffinity-purified leukotoxin and the cytotoxicity was analyzed by flow cyt

33 gnificantly affect the abundance of secreted leukotoxin, and we have developed a rapid (<2 h) method

34 tainly injure immune cells, the discovery of leukotoxin antagonism suggests that they may also play a

35 , suggesting a critical role for the diol in leukotoxin-associated respiratory disease.

36 assing amino acids 1 to 291, indicating that leukotoxin binding domain lies within amino acids 1 to 2

37 ed bovine-murine CD18 chimeras to locate the leukotoxin binding domain on CD18.

38 in on the leukocyte surface that is either a leukotoxin binding site or is required for stabilization

39 Leukotoxin binding was blocked by the addition of a neut

40 ing site or is required for stabilization of leukotoxin binding.

41 At moderately high concentrations of leukotoxin, bovine mononuclear cells were also induced t

42 lso resulted in the loss of the secretion of leukotoxin but not the ltxA transcription.

43 expression, production, and availability of leukotoxins by USA300, which in turn impact the cytotoxi

44 At low concentrations, the leukotoxin can activate ruminant leukocytes, whereas at

45 the accepted view, A. actinomycetemcomitans leukotoxin can indeed destroy erythrocytes and that the

46 Thus, while S. aureus leukotoxins can certainly injure immune cells, the disco

47 ion of bovine leukocytes with P. haemolytica leukotoxin caused marked cytoplasmic membrane blebbing (

48 At very high concentrations, leukotoxin caused necrotic cell death of bovine peripher

49 leukotoxin GH (LukGH; also known as LukAB), leukotoxin DE, and gamma-hemolysin.

50 We used a biologically inactive mutant leukotoxin (DeltaLktA) for comparison with LktA.

51 orphologic changes in bovine leukocytes were leukotoxin dependent, because they were significantly di

52 In vivo data also support the toxicity of leukotoxin diol.

53 After longer times of incubation, leukotoxin disappears from the supernatants, and its los

54 , has played an important role in generating leukotoxin diversity in ovine strains.

55 The leukotoxin does not have sequence similarity with any ot

56 rganism produces an exotoxin (referred to as leukotoxin) during logarithmic-phase growth that is a po

57 The Staphylococcus aureus leukotoxin ED (LukED) is a pore-forming toxin required f

58 oid cells and T lymphocytes by the S. aureus leukotoxin ED (LukED).

59 Our findings indicate that S. aureus leukotoxins enhance the host inflammatory response and i

60 a structure-based mechanism is proposed for leukotoxin epoxide hydrolysis.

61 of A. actinomycetemcomitans, which produced leukotoxin equivalent to the JP2 strain.

62 m sheep to cattle has been less important in leukotoxin evolution.

63 We found that leukotoxin expressed by the rough, adherent, clinical is

64 e and negative cis-acting sequences regulate leukotoxin expression and that IS1301 may increase trans

65 that identification of factors that regulate leukotoxin expression may provide insight into M. haemol

66 In contrast, no increase in leukotoxin expression occurred when cells were exposed t

67 x operon, cis-acting sequences that regulate leukotoxin expression were identified.

68 transcriptional activator of P. haemolytica leukotoxin expression.

69 nction as a positive cis-acting regulator of leukotoxin expression.

70 olytica that does not produce any detectable leukotoxin failed to exhibit the morphologic changes cha

71 determined if all staphylococcal bicomponent leukotoxin family members exhibit these properties.

72 /B (LukAB), the most divergent member of the leukotoxin family, exists as a heterodimer in solution r

73 ocidin F and S subunits of the two-component leukotoxin family.

74 ed polypeptides recognized affinity-purified leukotoxin from F. necrophorum culture supernatant in a

75 cat operon fusion by allelic exchange at the leukotoxin gene cluster (lktCABD).

76 The leukotoxin gene open reading frame (ORF; lktA) consists

77 30-bp deletion in the promoter region of the leukotoxin gene operon which results in enhanced transcr

78 inverse PCR led to the cloning of the entire leukotoxin gene.

79 ype 59 in Taipei in association with the PVL leukotoxin genes.

80 egion, indicative of a high level expression leukotoxin genotype, and conversion from a healthy perio

81 including Panton-Valentine leukocidin (PVL), leukotoxin GH (LukGH; also known as LukAB), leukotoxin D

82 tly identified a novel S. aureus leukotoxin (leukotoxin GH [LukGH]) using proteomics, but its role in

83 Leukotoxin has been reported to be toxic when injected i

84 espite extensive sequence conservation, each leukotoxin has unique properties, including disparate ce

85 Although these leukotoxins have been considered redundant due to their

86 ) demonstrate that two Staphylococcus aureus leukotoxins, HlgAB and LukED, target the Duffy antigen r

87 results suggest that increased expression of leukotoxin in strain IS1 does not arise from an outwardl

88 ined in order to determine the importance of leukotoxin in the pathogenesis of periodontitis.

89 They also reduce toxicity of leukotoxin in vivo in mice and prevent symptoms suggesti

90 ukAB also differs from the other bicomponent leukotoxins in that the S subunit (LukA) contains 33- an

91 of antibodies against Mannheimia haemolytica leukotoxin, in comparison to domestic sheep (DS, Ovis ar

92 staphylococcal superantigens, proteases, and leukotoxins, in addition to bacteriocins, was transferra

93 Leukotoxin induced a sustained elevation of intracellula

94 thermore, extracellular Ca2+ is required for leukotoxin-induced cytokine gene expression.

95 vage of the signal peptide and abrogation of leukotoxin-induced cytolysis of target cells.

96 hese leukocytes were absolutely resistant to leukotoxin-induced cytolysis.

97 Leukotoxin-induced intracellular Ca2+ elevation was inhi

98 se pneumonia and that the expression of this leukotoxin induces global changes in transcriptional lev

99 variant of CU1000N), secrete an abundance of leukotoxin into the culture supernatants during early st

100 Leukotoxin is a linoleic acic oxide produced by leukocyt

101 Leukotoxin is a member of the highly conserved repeat to

102 The secreted leukotoxin is active, as evidenced by its ability to kil

103 ovirus expression system we demonstrate that leukotoxin is only cytotoxic in the presence of epoxide

104 Actinobacillus actinomycetemcomitans leukotoxin is thought to be an important virulence facto

105 We recently identified a novel S. aureus leukotoxin (leukotoxin GH [LukGH]) using proteomics, but

106 Leukotoxin (Lkt) and lipopolysaccharide (LPS) are the mo

107 have shown that the Pasteurella haemolytica leukotoxin (LKT) and other RTX toxins bind beta(2)-integ

108 Pasteurella (Mannheimia) haemolytica leukotoxin (Lkt) causes cell type- and species-specific

109 ons of the RTX toxin Pasteurella haemolytica leukotoxin (LKT) contained LKT and LPS as the most promi

110 Leukotoxin (Lkt) is the most important virulence factor

111 Here, we demonstrate that the leukotoxin (LKT) of M. haemolytica causes NET formation

112 The ruminant-specific leukotoxin (Lkt) of Mannheimia haemolytica is the key vi

113 The effects of Pasteurella haemolytica leukotoxin (LKT) on the activity of phospholipase D (PLD

114 One example of such a toxin is the potent leukotoxin (LKT) produced by the bovine respiratory path

115 Leukotoxin (Lkt) secreted by Mannheimia (Pasteurella) ha

116 ovine neutrophils to Pasteurella haemolytica leukotoxin (LKT) stimulates the production of leukotrien

117 It produces a leukotoxin (LKT) that is an important virulence factor,

118 Foremost among these is a leukotoxin (LKT) that specifically kills ruminant leukoc

119 ipping fever pneumonia in cattle, produces a leukotoxin (LKT) which lyses ruminant leukocytes with hi

120 ys that amplified polymorphic regions in the leukotoxin (lkt), cytolethal distending toxin (cdt), maj

121 Its most important virulence factor is a leukotoxin (LKT), which is a member of the RTX family of

122 tory pathogen Mannheimia haemolytica and its leukotoxin (LKT).

123 ytes to Mannheimia (Pasteurella) haemolytica leukotoxin (Lkt).

124 toxin proteins, the Pasteurella haemolytica leukotoxin (LktA) and the enterohemorrhagic E. coli toxi

125 the site involved in Mannheimia haemolytica leukotoxin (LktA) binding and biological activity within

126 The leukotoxin (LktA) produced by Mannheimia haemolytica bin

127 Leukotoxin (Ltx) expressed by Aggregatibacter actinomyce

128 Actinobacillus actinomycetemcomitans leukotoxin (Ltx) is a member of the repeats-in-toxin (RT

129 The expression of the leukotoxin (ltx) operon varies significantly among Actin

130 Aggregatibacter actinomycetemcomitans leukotoxin (LtxA) is a major virulence factor that kills

131 Leukotoxin (LtxA) is a protein toxin that is secreted fr

132 of virulence factors, including an exotoxic leukotoxin (LtxA) that is a member of the repeats-in-tox

133 nobacillus) actinomycetemcomitans produces a leukotoxin (LtxA) that is a member of the RTX (repeats i

134 emcomitans produces a repeats-in-toxin (RTX) leukotoxin (LtxA) that selectively kills human immune ce

135 omitans, a periodontal pathogen, synthesizes leukotoxin (LtxA), a protein that helps the bacterium ev

136 inomycetemcomitans secretes a protein toxin, leukotoxin (LtxA), which helps the bacterium evade the h

137 A. actinomycetemcomitans produces leukotoxin (LtxA), which is a member of the RTX (repeats

138 t produces the RTX toxin (repeats in toxin), leukotoxin (LtxA).

139 ertain growth media due to the production of leukotoxin (LtxA).

140 The 2-component leukotoxin LukAB is critical for Staphylococcus aureus t

141 Here we demonstrate that the leukotoxins LukSF-PV and LukED antagonize each other's c

142 n-inhibition paradox is explained in part by leukotoxin-mediated apoptosis (i.e., activation-induced

143 ocked by the addition of a neutralizing anti-leukotoxin monoclonal antibody and was not detected when

144 cantly diminished in the presence of an anti-leukotoxin monoclonal antibody.

145 de enterotoxins, exotoxins, leukocidins, and leukotoxins not found in S. epidermidis.

146 of other bacterial species are secreted, the leukotoxin of A. actinomycetemcomitans is thought to rem

147 The leukotoxin of Mannheimia haemolytica is an important vir

148 The leukotoxin of Pasteurella (Mannheimia) haemolytica is be

149 e a specific binding site for P. haemolytica leukotoxin on bovine but not on porcine or human leukocy

150 aic structure and molecular evolution of the leukotoxin operon (lktCABD) was investigated by nucleoti

151 The recombinational exchanges within the leukotoxin operon have had greatest effect on LktA and p

152 played a major role in the evolution of the leukotoxin operon in ovine strains of M. haemolytica.

153 The DNA sequence upstream of the leukotoxin operon is divergently shared by P(lapT), whic

154 The leukotoxin operon of M. haemolytica has a complex mosaic

155 ion within the lktC transacylase gene of the leukotoxin operon was created.

156 shed (based on the promoter structure of the leukotoxin operon) into JP2 and non-JP2 genotypes, with

157 ound within the transcribed region of the Y4 leukotoxin operon.

158 nals to mediate the secretion of hemolysins, leukotoxins, or proteases from other bacterial species.

159 The entire leukotoxin ORF was expressed in Escherichia coli.

160 l whether the presentation of M. haemolytica leukotoxin peptides to T(h) cells by Ovca-DRB alleles is

161 toxic activity and a concomitant increase in leukotoxin polypeptide.

162 The bicomponent leukotoxins produced by Staphylococcus aureus kill host

163 In conclusion, we constructed a hyper-leukotoxin producing A. actinomycetemcomitans strain and

164 These hyper-leukotoxin producing strains with the 530 bp deletion ha

165 We have examined leukotoxin production and localization in rough (adheren

166 that could be responsible for modulation of leukotoxin production have not been defined.

167 IS1, but the mechanism leading to increased leukotoxin production was not determined.

168 ::cat operon fusion allowed us to quantitate leukotoxin promoter activity in P. haemolytica and to de

169 Extracts containing AlxA can bind to a leukotoxin promoter fragment.

170 analyses of ltxA RNA expression from defined leukotoxin promoter mutations in the chromosome identify

171 who had variants containing the full length leukotoxin promoter region (odds ratio = 22.5; 95% C.I.,

172 , and compared with the previously sequences leukotoxin promoter region of the high-producer strain J

173 ction of variants that had a deletion in the leukotoxin promoter region, indicative of a high level e

174 First, the leukotoxin promoter regions from moderately leukotoxic (

175 To perform cis/trans analyses, these three leukotoxin promoter regions were cloned into a plasmid u

176 host factor (IHF) binds to and represses the leukotoxin promoter, but neither CRP nor IHF is responsi

177 specifically at the -68 to -40 region of the leukotoxin promoter.

178 ovine alveolar macrophages with endotoxin or leukotoxin results in the induction of cytokine gene exp

179 itans, and strains expressing high levels of leukotoxin RNA are most often found at sites of periodon

180 The production of leukotoxin RNA can vary more than 50-fold among isolates

181 sequences in setting the disparate levels of leukotoxin RNA found, we have undertaken classical cis/t

182 he sequences responsible for down-regulating leukotoxin RNA levels in Y4 relative to JP2 are found wi

183 t Y4, despite the large insertion, initiates leukotoxin RNA synthesis at the same promoter as JP2 doe

184 etemcomitans; an mlc deletion mutant reduces leukotoxin RNA synthesis, and recombinant Mlc protein bi

185 gnificant in determining the lower levels of leukotoxin RNA.

186 e identified bovine CD18 as the receptor for leukotoxin secreted by Mannheimia (Pasteurella) haemolyt

187 Leukotoxin secreted by Mannheimia (Pasteurella) haemolyt

188 MorC is critical for membrane morphology and leukotoxin secretion in A. actinomycetemcomitans.

189 appropriate to consider a possible role for leukotoxin secretion in the pathogenesis of A. actinomyc

190 Thus leukotoxin should be regarded as a protoxin correspondin

191 Leukotoxin specifically lysed transfectants expressing b

192 The molecular evolution of the leukotoxin structural gene (lktA) of Mannheimia (Pasteur

193 lated RTX toxin, the Pasteurella haemolytica leukotoxin structural protein (LktA), can be activated i

194 protease K eliminated subsequent binding of leukotoxin, suggesting that there is a protein on the le

195 how these proteins work together to modulate leukotoxin synthesis.

196 comitans strains produce 10 to 20 times more leukotoxin than other minimally leukotoxic strains.

197 nfections, such as endocarditis, expresses a leukotoxin that acts on polymorphonuclear leukocytes and

198 inobacillus actinomycetemcomitans produces a leukotoxin that is considered a primary virulence factor

199 ed juvenile periodontitis, produces a potent leukotoxin that kills human neutrophils.

200 ative virulence factors including (a) an RTX leukotoxin that targets only neutrophils and monocytes a

201 S. aureus encodes pore-forming bi-component leukotoxins that are toxic towards neutrophils, but also

202 p to five different bicomponent pore-forming leukotoxins that lyse immune cells by forming pores in t

203 his is the first report of Ca2+ signaling by leukotoxin through a G-protein-coupled mechanism involvi

204 A. actinomycetemcomitans to surfaces, cause leukotoxin to be released from the bacterial cell.

205 in vitro, the relative contribution of this leukotoxin to invasive CA-MRSA infections such as pneumo

206 The ability of F. necrophorum leukotoxin to modulate the host immune system by its tox

207 We did not detect binding of biotinylated leukotoxin to porcine or human leukocytes, which have be

208 t factors responsible for the selectivity of leukotoxins towards different immune cells remain unknow

209 aken studies to identify other regulators of leukotoxin transcription and to demonstrate how these pr

210 ella haemolytica cosmid clone that activates leukotoxin transcription in Escherichia coli has been is

211 nstrate that, like that of other RTX toxins, leukotoxin transcription is environmentally regulated.

212 A model for the coordinated regulation of leukotoxin transcription is presented.

213 peats are a binding site for an activator of leukotoxin transcription.

214 indicate that an activator protein modulates leukotoxin transcription.

215 hat there are additional factors involved in leukotoxin transcriptional regulation.

216 Purified leukotoxin was able to lyse sheep and human erythrocytes

217 ometric analysis showed that the recombinant leukotoxin was active against bovine polymorphonuclear l

218 e as the epoxide, but reduce cytotoxicity of leukotoxin, which is activated by epoxide hydrolase to i

219 hich affect a variety of cell types, and the leukotoxins, which are cell-type- and species-specific.

220 virulence factors, including the bicomponent leukotoxins, which are critical for the cytotoxicity of

221 recent advances in our understanding of how leukotoxins work in receptor-mediated or receptor-indepe

222 more, in studies on A. actinomycetemcomitans leukotoxin workers should now consider this toxin's abil