18,496 research outputs found
Application of nitroarene dioxygenases in the design of novel strains that degrade chloronitrobenzenes.
Widespread application of chloronitrobenzenes as feedstocks for the production of industrial chemicals and pharmaceuticals has resulted in extensive environmental contamination with these toxic compounds, where they pose significant risks to the health of humans and wildlife. While biotreatment in general is an attractive solution for remediation, its effectiveness is limited with chloronitrobenzenes due to the small number of strains that can effectively mineralize these compounds and their ability to degrade only select isomers. To address this need, we created engineered strains with a novel degradation pathway that reduces the total number of steps required to convert chloronitrobenzenes into compounds of central metabolism. We examined the ability of 2-nitrotoluene 2,3-dioxygenase from Acidovorax sp. strain JS42, nitrobenzene 1,2-dioxygenase (NBDO) from Comamonas sp. strain JS765, as well as active-site mutants of NBDO to generate chlorocatechols from chloronitrobenzenes, and identified the most efficient enzymes. Introduction of the wild-type NBDO and the F293Q variant into Ralstonia sp. strain JS705, a strain carrying the modified ortho pathway for chlorocatechol metabolism, resulted in bacterial strains that were able to sustainably grow on all three chloronitrobenzene isomers without addition of co-substrates or co-inducers. These first-generation engineered strains demonstrate the utility of nitroarene dioxygenases in expanding the metabolic capabilities of bacteria and provide new options for improved biotreatment of chloronitrobenzene-contaminated sites
The decay of the and its nature as a molecule
We investigate the decay of with the assumption
that the is dynamically generated from the
interaction. In addition to the tree level diagrams that proceed via , we take into account also the final
state interactions of and . The
partial decay width and mass distributions of are
evaluated. We get a value for the partial decay width which, within errors, is
in fair agreement with the experimental result. The contribution from the tree
level diagrams is dominant, but the final state interactions have effects in
the mass distributions. The predicted mass distributions are significantly
different from phase space and tied to the nature of the
state.Comment: Published versio
, and the scalar bound state
We study the decay to based on the chiral unitary
model that generates the X(3720) resonance, and make predictions for the invariant mass distribution. From the shape of the distribution, the
existence of the resonance below threshold could be induced. We also predict
the rate of production of the X(3720) resonance to the mass
distribution with no free parameters.Comment: 9 pages, 17 figure
, and decays into and or
We study the , ,
, and decays and compare their mass distributions with those obtained for
the and .
The approach followed consist in a factorization of the weak part and the
hadronization part into a factor which is common to all the processes. Then
what makes the reactions different are some trivial Cabibbo-Kobayashi-Maskawa
matrix elements and the weight by which the different pairs of mesons appear in
a primary step plus their final state interaction. These elements are part of
the theory and thus, up to a global normalization factor, all the invariant
mass distributions are predicted with no free parameters. Comparison is made
with the limited experimental information available. Further comparison of
these results with coming LHCb measurements will be very valuable to make
progress in our understanding of the meson-meson interaction and the nature of
the low lying scalar meson resonances, and .Comment: 12 pages, 6 figures; v2: discussion added, references added, final
version published in EPJ
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