Helicobacter pylori in the human stomach:

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Helicobacter pylori in the human
stomach stability, diversity, and selection
Martin J. Blaser. M.D. Departments of Medicine
and Microbiology NYU School of Medicine New York,
NY 10016
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H. pylori and human disease
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Schematic course of H. pylori colonization
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Host-microbial interactions on mucosal surfaces
Flow
Metabolites
Direct Signals
Metabolites
Defense molecules
Toxins
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Schematic of interaction between co-evolved
colonizing microbe and host
Signals
Signals
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Co-evolution of obligate parasites and hosts
model 1
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Model of H. pylori equilibrium with host
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Dynamics and system parameters
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The free-living (mucus) bacterial cell population
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The adherent bacterial cell population
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The population of nutrients
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The population of effectors
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The host response population
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Schematic of the H. pylori population and the
host responses
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Immune response kinetics
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Initial transient persistence
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Initial transient elimination
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Immune response governor effect on population
sizes
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Competition early success
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Competition late success
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Co-evolution of obligate parasites and hosts
model 1
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Characteristics of 13 pairs of H. pylori isolates
from Dutch patients
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Phylogram of recA sequences from paired H. pylori
isolates from 13 patients obtained 7-10 years
apart
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AFLP analysis of paired strains from 13
individuals
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Model of H. pylori mutation and selection in
individual hosts
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Potential recombination mechanisms
Intra-chromosomal exchanges
Slipped-Strand Misalignment
Direct repeats
A B C
A B C
C
C
B
Replication
A
A
B
C
Slipped pairing and replication
C
C
B
A
A
C
Deletion
A
C
Deletion of B
Deletion of B
Byzmek and Lovett, PNAS 988319-8325
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Types of O-antigens of H. pylori
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Structure of Lewis antigens
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Hypothesis
H. pylori Lewis antigen expression is an
adaptation to permit persistence in an individual
host. H. pylori cells are pluripotential and can
predominantly express Lex, Ley or neither. The
host Lewis phenotype selects for the particular
level of H. pylori Lewis expression.
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Relation between H. pylori Lewis expression and
host Lewis phenotype
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Adaptation of H. pylori to individual hosts
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Selection plus mutation model
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Schematic of experimental H.
pylori infection of rodents
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H. pylori Ley expression in mice actual and
simulated
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Schematic of Lewis antigen synthesis in H.
pylori
GlcNAc-R
galT
ß-(1,3)galT
b-(1,4) galactosyltransferase
b-(1,3) galactosyltransferase
Type 1 / Lewis C
Type 2 / LacNAc
futA/futB
a-(1,3/4) fucosyltransferases
Lex
Lea
futC
a-(1,2) fucosyltransferase
Ley
Leb
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Regions in the Le antigen synthesis genes that
are prone to intragenomic recombination
ß-(1,4)galT
Variable upstream region
ß-(1,3)galT
Poly-C tract
21bp repeats
futA/futB
Poly-C tract
futC
Poly-C tract
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Difficulties in sequencing homopolymeric DNA
tracts
ß-(1,3)galT
Poly-C tract

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Interstrain diversity in the number of 21
bp-repeats in ß-(1,3)galT
ß-(1,3)galT
Palindrome Poly-C tract 21bp
repeats
500 300 100
200
J99
26695
HP1
J166
97-762
B128
HPK5
HPK1
CH4
97-690
No DNA
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Ley synthesis
Ley
Lex
GlcNAc - R
Type 2 / LacNAc
galT
futA and futB
futC
b-(1,4) galactosyltransferase
a-(1,3/4) fucosyltransferases
a-(1,2) fucosyltransferase
futC
poly-C tract
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Isolation of single colonies strain J166

• H. pylori strain J166 expresses Lex and Ley in
  measurable amounts.
• Hypothesis The J166 population contains
• Ley phenotypic variants that differ from the wild
  type genotype.

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Overall Le expression for 379 individual colonies
from H. pylori strain J166

• Statistic Ley Lex

0.66 0.54 0.45 0.28 0.67
1.01 0.47 1.17 0.93 1.26
Mean SD Median 25 quartile 75 quartile
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Relation of Lex and Ley values in individual
colonies organized according to Ley values
2.50
2.00
1.50
Mean values
1.00
0.50
0.00
0-0.20
1-1.19
1.4-1.59
2.0-2.19
0.20-0.40
0.40-0.59
0.60-0.79
0.80-0.99
1.20-1.39
1.60-1.79
1.80-1.99
2.20-2.39
Ley ranges
Lex mean TCMO
Ley Mean TCMO
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Relation between Lex and Ley values in 379
single J166 colonies of H. pylori strain J166
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Regions in the Le antigen synthesis genes that
are prone to intragenomic recombination
ß-(1,4)galT
Variable upstream region
ß-(1,3)galT
Poly-C tract
21bp repeats
futA and futB
Poly-C tract
futC
Poly-C tract
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Relationship between Ley expression and futC
genotype
futC
Strain
ODU Values
of cytosines
Sequence
Frame
Lex
Ley
OUT
10
2.22
0.53
J166
9
IN
0.37
0.75
MC 6
OUT
MC 31
1.46
0.04
10
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Schematic of host resource utilization by H.
pylori populations
(Microniches, 1n)
Number (H. pylori cells, 1z)
Time (Years, 0x)
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Relation of host phenotype and H. pylori Lewis
phenotype
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futC sequences in 4 monkey isolates
Frame In Out Out Out In
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Comparison of Lewis antigen synthesis genes in
strains J99 and 98-169

• Frame Status
• Gene J166 98-169 Comment

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futB sequences in strains 98-169 and J166
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Deduced futB sequences in strains 98-169 and J66
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Co-evolution of obligate parasites and hosts
model 4
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Model of structures implicit in ecosystems
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Recombination hotspots in M. tuberculosis
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5
4
3
2
1
0
Size of potential recombination interval (Log10bp)
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4
4
3
3
2
2
1
1
39.37
39.47
31.23
39.27
31.19
31.21
Chromosomal location (x 100,000 bp) of middle
nucleotide between paired identical repeat
sequences
Rv3512
Rv3513
Rv3511
Rv3509
Rv3510
Rv3514
Rv3507
Rv3508
Rv2814c
Rv2815c
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Complex adaptive systems
Pay attention to neighbors Negative feedback
loops at local levels More is different Ignorance
is useful Randomness encouraged, within limits
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Contributors

• Mathematics Denise Kirschner, Glenn Webb
• Informatics David Pride, Rahul Aras, Ariane
  Tschumi, Yasu Harasaki, Henry Feldman
• Diversity Ernst Kuipers, Stephan Meuwissen,
  Dawn Israel
• Lewis Hans Peter Wirth, Manquiao Yang, Richard
  Peek, Andre Dubois, Douglas Berg, Edgardo
  Sanabria-Valentin, Marie Colbert, Daniel Hwang,
  Adam Pont