Science,
Journal Year:
2017,
Volume and Issue:
357(6351), P. 570 - 575
Published: Aug. 11, 2017
Healthy
guts
exclude
oxygen
Normally,
the
lumen
of
colon
lacks
oxygen.
Fastidiously
anaerobic
butyrate-producing
bacteria
thrive
in
colon;
by
ablating
these
organisms,
antibiotic
treatment
removes
butyrate.
Byndloss
et
al.
discovered
that
loss
butyrate
deranges
metabolic
signaling
gut
cells
(see
Perspective
Cani).
This
induces
nitric
oxidase
to
generate
nitrate
and
disables
β-oxidation
epithelial
would
otherwise
mop
up
stray
before
it
enters
colon.
Simultaneously,
regulatory
T
retreat,
inflammation
is
unchecked,
which
contributes
yet
more
species
Then,
facultative
aerobic
pathogens,
such
as
Escherichia
coli
Salmonella
enterica
,
can
take
advantage
altered
environment
outgrow
any
antibiotic-crippled
benign
anaerobes.
Science
this
issue
p.
570
;
see
also
548
Methods in Ecology and Evolution,
Journal Year:
2016,
Volume and Issue:
8(1), P. 28 - 36
Published: Aug. 16, 2016
Summary
We
present
an
r
package,
ggtree
,
which
provides
programmable
visualization
and
annotation
of
phylogenetic
trees.
can
read
more
tree
file
formats
than
other
softwares,
including
newick
nexus
NHX
phylip
jplace
formats,
support
phylo,
multiphylo,
phylo4,
phylo4d,
obkdata
phyloseq
objects
defined
in
packages.
It
also
extract
the
tree/branch/node‐specific
data
from
analysis
outputs
beast
epa
hyphy
paml
phylodog
pplacer
r8s
raxml
revbayes
software,
allows
using
these
to
annotate
tree.
The
package
colouring
a
by
numerical/categorical
node
attributes,
manipulating
rotating,
collapsing
zooming
out
clades,
highlighting
user
selected
clades
or
operational
taxonomic
units
exploration
large
into
portion.
A
two‐dimensional
be
drawn
scaling
width
based
on
attribute
nodes.
annotated
with
associated
numerical
matrix
(as
heat
map),
multiple
sequence
alignment,
subplots
silhouette
images.
is
released
under
artistic‐2.0
license
.
source
code
documents
are
freely
available
through
bioconductor
(
http://www.bioconductor.org/packages/ggtree
).
PLoS Computational Biology,
Journal Year:
2014,
Volume and Issue:
10(4), P. e1003531 - e1003531
Published: April 3, 2014
Current
practice
in
the
normalization
of
microbiome
count
data
is
inefficient
statistical
sense.
For
apparently
historical
reasons,
common
approach
either
to
use
simple
proportions
(which
does
not
address
heteroscedasticity)
or
rarefying
counts,
even
though
both
these
approaches
are
inappropriate
for
detection
differentially
abundant
species.
Well-established
theory
available
that
simultaneously
accounts
library
size
differences
and
biological
variability
using
an
appropriate
mixture
model.
Moreover,
specific
implementations
DNA
sequencing
read
(based
on
a
Negative
Binomial
model
instance)
already
RNA-Seq
focused
R
packages
such
as
edgeR
DESeq.
Here
we
summarize
supporting
simulations
empirical
demonstrate
substantial
improvements
provided
by
relevant
framework
over
rarefying.
We
show
how
rarefied
counts
result
high
rate
false
positives
tests
species
across
sample
classes.
Regarding
sample-wise
clustering,
also
procedure
often
discards
samples
can
be
accurately
clustered
alternative
methods.
further
compare
different
methods
with
recently-described
zero-inflated
Gaussian
mixture,
implemented
package
called
metagenomeSeq.
find
metagenomeSeq
performs
well
when
there
adequate
number
replicates,
but
it
nevertheless
tends
toward
higher
positive
rate.
Based
results
well-established
theory,
advocate
investigators
avoid
altogether.
have
microbiome-specific
extensions
tools
package,
phyloseq.
Microbiome,
Journal Year:
2018,
Volume and Issue:
6(1)
Published: Dec. 1, 2018
The
accuracy
of
microbial
community
surveys
based
on
marker-gene
and
metagenomic
sequencing
(MGS)
suffers
from
the
presence
contaminants—DNA
sequences
not
truly
present
in
sample.
Contaminants
come
various
sources,
including
reagents.
Appropriate
laboratory
practices
can
reduce
contamination,
but
do
eliminate
it.
Here
we
introduce
decontam
(
https://github.com/benjjneb/decontam
),
an
open-source
R
package
that
implements
a
statistical
classification
procedure
identifies
contaminants
MGS
data
two
widely
reproduced
patterns:
appear
at
higher
frequencies
low-concentration
samples
are
often
found
negative
controls.
Decontam
classified
amplicon
sequence
variants
(ASVs)
human
oral
dataset
consistently
with
prior
microscopic
observations
taxa
inhabiting
environment
previous
reports
contaminant
taxa.
In
metagenomics
measurements
dilution
series,
substantially
reduced
technical
variation
arising
different
protocols.
application
to
recently
published
datasets
corroborated
extended
their
conclusions
little
evidence
existed
for
indigenous
placenta
microbiome
some
low-frequency
seemingly
associated
preterm
birth
were
contaminants.
improves
quality
by
identifying
removing
DNA
sequences.
integrates
easily
existing
workflows
allows
researchers
generate
more
accurate
profiles
communities
no
additional
cost.
Frontiers in Microbiology,
Journal Year:
2017,
Volume and Issue:
8
Published: Nov. 15, 2017
Datasets
collected
by
high-throughput
sequencing
(HTS)
of
16S
rRNA
gene
amplimers,
metagenomes
or
metatranscriptomes
are
commonplace
and
being
used
to
study
human
disease
states,
ecological
differences
between
sites,
the
built
environment.
There
is
increasing
awareness
that
microbiome
datasets
generated
HTS
compositional
because
they
have
an
arbitrary
total
imposed
instrument.
However,
many
investigators
either
unaware
this
assume
specific
properties
data.
The
purpose
review
alert
dangers
inherent
in
ignoring
nature
data,
point
out
derived
from
studies
can
should
be
treated
as
compositions
at
all
stages
analysis.
We
briefly
introduce
illustrate
pathologies
occur
when
data
analyzed
inappropriately,
finally
give
guidance
resources
examples
for
analysis
using
Microbiome,
Journal Year:
2017,
Volume and Issue:
5(1)
Published: March 3, 2017
Data
from
16S
ribosomal
RNA
(rRNA)
amplicon
sequencing
present
challenges
to
ecological
and
statistical
interpretation.
In
particular,
library
sizes
often
vary
over
several
ranges
of
magnitude,
the
data
contains
many
zeros.
Although
we
are
typically
interested
in
comparing
relative
abundance
taxa
ecosystem
two
or
more
groups,
can
only
measure
taxon
specimens
obtained
ecosystems.
Because
comparison
specimen
is
not
equivalent
ecosystems,
this
presents
a
special
challenge.
Second,
because
(as
well
as
ecosystem)
sum
1,
these
compositional
data.
constrained
by
simplex
(sum
1)
unconstrained
Euclidean
space,
standard
methods
analysis
applicable.
Here,
evaluate
how
impact
performance
existing
normalization
differential
analyses.
Effects
on
normalization:
Most
enable
successful
clustering
samples
according
biological
origin
when
groups
differ
substantially
their
overall
microbial
composition.
Rarefying
clearly
clusters
than
other
techniques
do
for
ordination
metrics
based
presence
absence.
Alternate
measures
potentially
vulnerable
artifacts
due
size.
testing:
We
build
previous
work
seven
proposed
using
rarefied
raw
Our
simulation
studies
suggest
that
false
discovery
rates
abundance-testing
increased
rarefying
itself,
although
course
results
loss
sensitivity
elimination
portion
available
For
with
large
(~10×)
differences
average
size,
lowers
rate.
DESeq2,
without
addition
constant,
smaller
datasets
(<20
per
group)
but
tends
towards
higher
rate
samples,
very
uneven
sizes,
and/or
effects.
drawing
inferences
regarding
ecosystem,
composition
microbiomes
(ANCOM)
sensitive
(for
>20
also
critically
method
tested
has
good
control
These
findings
guide
which
use
characteristics
given
study.
Nucleic Acids Research,
Journal Year:
2017,
Volume and Issue:
45(W1), P. W180 - W188
Published: April 12, 2017
The
widespread
application
of
next-generation
sequencing
technologies
has
revolutionized
microbiome
research
by
enabling
high-throughput
profiling
the
genetic
contents
microbial
communities.
How
to
analyze
resulting
large
complex
datasets
remains
a
key
challenge
in
current
studies.
Over
past
decade,
powerful
computational
pipelines
and
robust
protocols
have
been
established
enable
efficient
raw
data
processing
annotation.
focus
shifted
toward
downstream
statistical
analysis
functional
interpretation.
Here,
we
introduce
MicrobiomeAnalyst,
user-friendly
tool
that
integrates
recent
progress
statistics
visualization
techniques,
coupled
with
novel
knowledge
bases,
comprehensive
common
outputs
produced
from
MicrobiomeAnalyst
contains
four
modules
-
Marker
Data
Profiling
module
offers
various
options
for
community
profiling,
comparative
prediction
based
on
16S
rRNA
marker
gene
data;
Shotgun
supports
exploratory
analysis,
metabolic
network
shotgun
metagenomics
or
metatranscriptomics
Taxon
Set
Enrichment
Analysis
helps
interpret
taxonomic
signatures
via
enrichment
against
>300
taxon
sets
manually
curated
literature
public
databases;
finally,
Projection
Public
allows
users
visually
explore
their
reference
pattern
discovery
biological
insights.
is
freely
available
at
http://www.microbiomeanalyst.ca.
Science Translational Medicine,
Journal Year:
2015,
Volume and Issue:
7(307)
Published: Sept. 30, 2015
Asthma
is
the
most
prevalent
pediatric
chronic
disease
and
affects
more
than
300
million
people
worldwide.
Recent
evidence
in
mice
has
identified
a
"critical
window"
early
life
where
gut
microbial
changes
(dysbiosis)
are
influential
experimental
asthma.
However,
current
research
yet
to
establish
whether
these
precede
or
involved
human
We
compared
microbiota
of
319
subjects
enrolled
Canadian
Healthy
Infant
Longitudinal
Development
(CHILD)
Study,
show
that
infants
at
risk
asthma
exhibited
transient
dysbiosis
during
first
100
days
life.
The
relative
abundance
bacterial
genera
Lachnospira,
Veillonella,
Faecalibacterium,
Rothia
was
significantly
decreased
children
This
reduction
taxa
accompanied
by
reduced
levels
fecal
acetate
dysregulation
enterohepatic
metabolites.
Inoculation
germ-free
with
four
ameliorated
airway
inflammation
their
adult
progeny,
demonstrating
causal
role
averting
development.
These
results
enhance
potential
for
future
microbe-based
diagnostics
therapies,
potentially
form
probiotics,
prevent
development
other
related
allergic
diseases
children.