14 research outputs found
Differential attraction and repulsion of Staphylococcus aureus and Pseudomonas aeruginosa on molecularly smooth titanium films
Magnetron sputtering techniques were used to prepare molecularly smooth titanium thin films
possessing an average roughness between 0.18 nm and 0.52 nm over 5 μm × 5 μm AFM scanning
areas. Films with an average roughness of 0.52 nm or lower were found to restrict the extent
of P. aeruginosa cell attachment, with less than 0.5% of all available cells being
retained on the surface. The attachment of S. aureus cells was also limited on films
with an average surface roughness of 0.52 nm, however they exhibited a remarkable propensity
for attachment on the nano-smoother 0.18 nm average surface roughness films, with the
attachment density being almost twice as great as that observed on the nano-rougher film.
The difference in attachment behaviour can be attributed to the difference in morphology of
the rod-shaped P. aeruginosa compared to the spherical S. aureus cells
A rapid change in P-element-induced hybrid dysgenesis status in Ukrainian populations of Drosophila melanogaster
Hierarchical tissue organization as a general mechanism to limit the accumulation of somatic mutations
How can tissues generate large numbers of cells, yet keep the divisional load
(the number of divisions along cell lineages) low in order to curtail the
accumulation of somatic mutations and reduce the risk of cancer? To answer the
question we consider a general model of hierarchically organized self-renewing
tissues and show that the lifetime divisional load of such a tissue is
independent of the details of the cell differentiation processes, and depends
only on two structural and two dynamical parameters. Our results demonstrate
that a strict analytical relationship exists between two seemingly disparate
characteristics of self-renewing tissues: divisional load and tissue
organization. Most remarkably, we find that a sufficient number of
progressively slower dividing cell types can be almost as efficient in
minimizing the divisional load, as non-renewing tissues. We argue that one of
the main functions of tissue-specific stem cells and differentiation
hierarchies is the prevention of cancer.Comment: To appear in Nature Communication