Mrub_1325, Mrub_1326, Mrub_1327, and Mrub_1328 are orthologs of B_3454, B_3455, B_3457, B_3458, respectively found in \u3cem\u3eEscherichia coli\u3c/em\u3e coding for a Branched Chain Amino Acid ATP Binding Cassette (ABC) Transporter System

In this project we investigated the biological function of the genes Mrub_1325, Mrub_1326, Mrub_1327, and Mrub_1328 (KEGG map number 02010). We predict these genes encode components of a Branched Chain Amino Acid ATP Binding Cassette (ABC) transporter: 1) Mrub_1325 (DNA coordinates 1357399-1358130 on the reverse strand) encodes the ATP binding domain; 2) Mrub_1326 (DNA coordinates 1358127-1359899 on the reverse strand) encodes the ATP-binding domain and permease domain; 3) Mrub_1327 (DNA coordinates 1359899-1360930 on the reverse strand) encodes a permease domain; and 4)Mrub_1328 (DNA coordinates 1711022-1712185 on the reverse strand) encodes the substrate binding domain. This system is not predicted to have a solute binding protein, which is a component of most ABC transporters. This transport system is found in E. coli K12 MG1655, the predicted orthologs of Mrub_1325, Mrub_1326, Mrub_1327, and Mrub_1328, livF, livG, livH, and livK respectively, are b3454, b3455, b3457, and b3458, form a livFGHK operon encoding an ABC transporter for branched chain amino acid transport. Mrub_1326 is likely a fused protein of both livG and livM suggesting it may also be orthologous to b3456. This project is part of the Meiothermus ruber genome analysis project, which predicts gene function using the bioinformatics tools collected under the umbrella of the Guiding Education through Novel Investigation –Annotation Collaboration Toolkit (GENI-ACT)

Critical invariant circles in asymmetric and multiharmonic generalized standard maps

Invariant circles play an important role as barriers to transport in the dynamics of area-pre- serving maps. KAM theory guarantees the persistence of some circles for near-integrable maps, but far from the integrable case all circles can be destroyed. A standard method for determining the existence or nonexistence of a circle, Greene’s residue criterion, requires the computation of long-period orbits, which can be difficult if the map has no reversing symmetry. We use de la Llave’s quasi-Newton, Fourier-based scheme to numer- ically compute the conjugacy of a Diophantine circle conjugate to rigid rotation, and the singularity of a norm of a derivative of the conjugacy to predict criticality. We study near-critical conjugacies for families of rotational invariant circles in generalizations of Chirikov’s standard map. A first goal is to obtain evidence to support the long-standing conjecture that when cir- cles breakup they form cantori, as is known for twist maps by Aubry–Mather theory. The location of the largest gaps is compared to the maxima of the potential when anti-integra- ble theory applies. A second goal is to support the conjecture that locally most robust cir- cles have noble rotation numbers, even when the map is not reversible. We show that relative robustness varies inversely with the discriminant for rotation numbers in qua- dratic algebraic fields. Finally, we observe that the rotation number of the globally most robust circle generically appears to be a piecewise-constant function in two-parameter families of maps

Manufactured nanoparticles in the aquatic environment-biochemical responses on freshwater organisms: A critical overview

The enormous investments in nanotechnology have led to an exponential increase of new manufactured nano-enabled materials whose impact in the aquatic systems is still largely unknown. Ecotoxicity and nanosafety studies mostly resulted in contradictory results and generally failed to clearly identify biological patterns that could be related specifically to nanotoxicity. Generation of reactive oxygen species (ROS) is one of the most discussed nanotoxicity mechanism in literature. ROS can induce oxidative stress (OS), resulting in cyto- and genotoxicity. The ROS overproduction can trigger the induction of anti-oxidant enzymes such as catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidases (GPx), which are used as biomarkers of response. A critical overview of the biochemical responses induced by the presence of NPs on freshwater organisms is performed with a strong interest on indicators of ROS and general stress. A special focus will be given to the NPs transformations, including aggregation, and dissolution, in the exposure media and the produced biochemical endpoints. (C) 2015 Elsevier B.V. All rights reserved