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Cyclic amp: A polyhedral signalling molecule in plants
Full text linkThe cyclic nucleotide cAMP (3′,5′‐cyclic adenosine monophosphate) is nowadays recognised as an important signalling molecule in plants, involved in many molecular processes, including sensing and response to biotic and abiotic environmental stresses. The validation of a functional cAMP‐dependent signalling system in higher plants has spurred a great scientific interest on the polyhedral role of cAMP, as it actively participates in plant adaptation to external stimuli, in addition to the regulation of physiological processes. The complex architecture of cAMP‐dependent pathways is far from being fully understood, because the actors of these pathways and their downstream target proteins remain largely unidentified. Recently, a genetic strategy was effectively used to lower cAMP cytosolic levels and hence shed light on the consequences of cAMP deficiency in plant cells. This review aims to provide an integrated overview of the current state of knowledge on cAMP’s role in plant growth and response to environmental stress. Current knowledge of the molecular components and the mechanisms of cAMP signalling events is summarised
"cAMP-SPONGE": A NEW GENETIC TOOL TO INVESTIGATE THE ROLE OF cAMP IN PLANTS
No full textCyclic
AMP
is
a
well
known
second
messenger
which
regulates
a
wide
variety
of
cellular
responses
in
living
organisms
such
as
bacteria,
fungi,
and
animals.
On
the
contrary,
its
presence
and
its
role
in
plants
have
been
debated
for
decades.
The
skepticism
was
finally
overcome
with
the
use
of
mass
spectrometry
that
provided
unequivocal
evidence
of
its
presence
in
higher
plants.
The
information
on
the
biological
function
of
cAMP
in
plants
remains
very
limited,
mainly
because
its
content
in
plant
cells
is
significantly
lower
than
in
other
organisms.
To
date,
the
cAMP
involvement
in
several
processes
of
higher
plants,
including
cell
cycle
regulation,
growth
and
reorientation
of
the
pollen
tube,
seed
germination
and
defense
processes
has
been
reported.
However,
in
plants,
the
mechanisms
involved
in
the
cAMP-dependent
signal
transduction
are
yet
unknown,
especially
for
the
failure
to
identify
a
kinase
that
responds
specifically
to
cellular
changes
in
cAMP
concentration.
Understanding
both
the
biological
events
specifically
attributable
to
cAMP,
and
the
mechanisms
by
which
these
processes
are
regulated,
through
the
combination
of
quantitative
data
with
mathematical models, is a challenge for the study of plant signal transduction.
In
order
to
obtain
more
information
on
the
role
of
cAMP
in
plants
we
generated
tobacco
Bright
yellow-2
(TBY-2)
lines
that
constitutively
express
a
non-invasive
tool,
the
“cAMP-sponge”,
able
to
selectively
perturb
the
cAMP
concentration
(Lefkimmiatis
et
al,
2009).
The
cAMP-sponge
is
composed
of
two
high-affinity
cAMP
binding
domains
of
the
regulatory
subunits
I
beta
of
human
protein
kinase
A
(PKARIbeta).
These
domains
have
been
engineered
to
be
unable
to
interact
with
the
catalytic
subunit
of
PKA
itself
or
to
homodimerize.
This
construct
binds
with
high
affinity
cAMP
but
not
cGMP.
The
cAMP-sponge
in
frame
with
the
reporter
gene
mCherry
has
been
inserted
in
the
binary
vector
pGreenII
(kan)
under
the
control
of
the
strong
constitutive
promoter
CaMV
35S.The
construct
has
been
transferred
into
Agrobacterium
tumefaciens
GV3101
strain
through
electroporation
and
mobilized
into
TBY-2
cells
via
A.
tumefaciens
-mediated
transformation.
Transgenic
TBY-2
lines
have
been
selected
in
the
presence
of
kanamycin,
and
several independent transgenic lines obtained.
Transformed
lines
have
been
analyzed
through
PCR,
RT-PCR
and
immunoblotting
to
assess
trans-gene
integration
and
mRNA
and
protein
expression.
Finally
the
effect
of
the
lower
levels
of
cAMP on the growth of TBY-2 cells has been analyzed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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