Habitat selection by Calomys musculinus (Muridae, Sigmodontinae) in crop areas of the pampean region, Argentina

Calomys musculinus (Muridae, Sigmodontinae) is a small rodent species found in most central and northern Argentina. It is the reservoir of the Junin virus, ethiological agent of the Argentine Hemorrhagic Fever (FHA). In the present work we studied habitat selection by C. musculinus at different spatial scales in rural habitats where the landscape is mainly formed by cropfields, surrounded by weedy margins (borders). We found that C. musculinus selects borders over cropfields, but there were not differences between types of fields or types of borders. The structure of the spatial heterogeneity, which is mainly grouped between macrohabitats due to agrarian labors, did not allow to detect habitat selection, within cropfields and borders, for habitat patches larger than individual trap sites. Distribution between fields and borders was related to the green plant cover in early autumn, probably because of specific requirements of reproductive individuals. Within these habitats, we found differences in captures according to the presence of some plant species, which varied according to the season and the habitat

Controlled assembly of SNAP-PNA-fluorophore systems on DNA templates to produce fluorescence resonance energy transfer

The SNAP protein is a widely used self-labeling tag that can be used for tracking protein localization and trafficking in living systems. A model system providing controlled alignment of SNAP-tag units can provide a new way to study clustering of fusion proteins. In this work, fluorescent SNAP-PNA conjugates were controllably assembled on DNA frameworks forming dimers, trimers, and tetramers. Modification of peptide nucleic acid (PNA) with the O6-benzyl guanine (BG) group allowed the generation of site-selective covalent links between PNA and the SNAP protein. The modified BG-PNAs were labeled with fluorescent Atto dyes and subsequently chemo-selectively conjugated to SNAP protein. Efficient assembly into dimer and oligomer forms was verified via size exclusion chromatography (SEC), electrophoresis (SDS-PAGE), and fluorescence spectroscopy. DNA directed assembly of homo- and hetero-dimers of SNAP-PNA constructs induced homo- and hetero-FRET, respectively. Longer DNA scaffolds controllably aligned similar fluorescent SNAP-PNA constructs into higher oligomers exhibiting homo-FRET. The combined SEC and homo-FRET studies indicated the 1:1 and saturated assemblies of SNAP-PNA-fluorophore:DNA formed preferentially in this system. This suggested a kinetic/stoichiometric model of assembly rather than binomially distributed products. These BG-PNA-fluorophore building blocks allow facile introduction of fluorophores and/or assembly directing moieties onto any protein containing SNAP. Template directed assembly of PNA modified SNAP proteins may be used to investigate clustering behavior both with and without fluorescent labels which may find use in the study of assembly processes in cells

TALEN-mediated editing of the mouse Y chromosome

The functional study of Y chromosome genes has been hindered by a lack of mouse models with specific Y chromosome mutations. We used transcription activator-like effector nuclease (TALEN)-mediated gene editing in mouse embryonic stem cells (mESCs) to produce mice with targeted gene disruptions and insertions in two Y-linked genes—Sry and Uty. TALEN-mediated gene editing is a useful tool for dissecting the biology of the Y chromosome.National Institutes of Health (U.S.) (US NIH grant R01-HG000257)National Institutes of Health (U.S.) (US NIH grant R01-CA084198)National Institutes of Health (U.S.) (US NIH grant R37-HD045022)Croucher Foundation (Scholarship)Howard Hughes Medical Institute (Investigator