279 research outputs found
Effects of Growth Hormone (GH) Overexpression in Signaling Cascades Involved in Promotion of Cell Proliferation and Survival
Espejos profundos : un atisbo a la narrativa fronteriza contemporaÌnea = Deep mirrors : a study of the contemporary border narrative
Isolation of Cellular Clones of Murine Melanoma Resistants to the Photodynamic Therapy and Characterization of Some Mechanisms Involved in the Radioresistance
Understanding the impact of temperate bacteriophages on their lysogens through transcriptomics
SUMMARY: This protocol enables the impact of prophages on their hosts to be revealed. Bacterial cultures are synchronized using conditions that best support the lysogenic state, limiting spontaneous induction. RT-qPCR unequivocally distinguishes prophage-restricted genes and those uncoupled from phage control from those that are expressed during the lytic replication cycle. ABSTRACT: Temperate phages are found integrated as prophages in the majority of bacterial genomes. Some prophages are cryptic and fixed in the bacterial chromosome, but others are active and can be triggered into a replicative form either spontaneously or by exposure to inducing factors. Prophages are commonly associated with the ability to confer toxin production or other virulence-associated traits on their host cell. More recent studies have shown they can play a much bigger role in altering the physiology of their hosts. The technique described here has enabled us to investigate how prophages affect gene expression in the opportunistic bacterium Pseudomonas aeruginosa.In this protocol, a portion of bacterial cells within a lysogenic culture is made to undergo lytic replication (spontaneous induction) with a high level of expression per cell of late phage genes, such as those associated with the assembly of phage particles, thus masking the low-level gene expression associated with lysogen-restricted gene expression. In this work, the growth of the wild-type P. aeruginosa strain PAO1 was compared with that of isogenic lysogens carrying different combinations of prophages from the Liverpool Epidemic Strain (LES) LESB58
Planck intermediate results. VIII. Filaments between interacting clusters
About half of the baryons of the Universe are expected to be in the form of
filaments of hot and low density intergalactic medium. Most of these baryons
remain undetected even by the most advanced X-ray observatories which are
limited in sensitivity to the diffuse low density medium. The Planck satellite
has provided hundreds of detections of the hot gas in clusters of galaxies via
the thermal Sunyaev-Zel'dovich (tSZ) effect and is an ideal instrument for
studying extended low density media through the tSZ effect. In this paper we
use the Planck data to search for signatures of a fraction of these missing
baryons between pairs of galaxy clusters. Cluster pairs are good candidates for
searching for the hotter and denser phase of the intergalactic medium (which is
more easily observed through the SZ effect). Using an X-ray catalogue of
clusters and the Planck data, we select physical pairs of clusters as
candidates. Using the Planck data we construct a local map of the tSZ effect
centered on each pair of galaxy clusters. ROSAT data is used to construct X-ray
maps of these pairs. After having modelled and subtracted the tSZ effect and
X-ray emission for each cluster in the pair we study the residuals on both the
SZ and X-ray maps. For the merging cluster pair A399-A401 we observe a
significant tSZ effect signal in the intercluster region beyond the virial
radii of the clusters. A joint X-ray SZ analysis allows us to constrain the
temperature and density of this intercluster medium. We obtain a temperature of
kT = 7.1 +- 0.9, keV (consistent with previous estimates) and a baryon density
of (3.7 +- 0.2)x10^-4, cm^-3. The Planck satellite mission has provided the
first SZ detection of the hot and diffuse intercluster gas.Comment: Accepted by A&
Seasonal varia,on of zooplankton and environmental condi,ons along a transect in the Gulf of Cadiz
Planck intermediate results: IV. the XMM-Newton validation programme for new Planck galaxy clusters
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