EST-database search of plant defensins - an example using sugarcane, a large and complex genome.

EST (Expressed Sequence Tags) databases are increasing in number and size, especially regarding cultivated plants. Sugarcane is one of the most important tropical and subtropical crops, presenting a complex polyploid genome of hybrid origin, bearing a challenge for the understanding of genetic processes in higher plants. In the present work a general search was carried out on the largest Sugarcane EST Database (SUCEST) that includes 237,954 ESTs aiming to identify defensin antimicrobial peptides - a class of small, basic, cysteine-rich peptides distributed throughout the kingdoms. Using a computational approach 17 new defensin isoforms could be identified. Main steps for the search, characterization and evaluation of the defensin expression profile are presented. Prevalent expression tissues were leaf roll, lateral bark, root apex, base of inflorescence, developing seed, and calli. Bioinformatics and phylogenetic analysis of the primary structure of the sugarcane defensin candidates as well as the 3D structures obtained by comparative modeling support their role as antimicrobials

Late Pleistocene echimyid rodents (Rodentia, Hystricognathi) from northern Brazil

ABSTRACT Echimyidae (spiny rats, tree rats and the coypu) is the most diverse family of extant South American hystricognath rodents (caviomorphs). Today, they live in tropical forests (Amazonian, coastal and Andean forests), occasionally in more open xeric habitats in the Cerrado and Caatinga of northern South America, and open areas across the southern portion of the continent (Myocastor). The Quaternary fossil record of this family remains poorly studied. Here, we describe the fossil echimyids found in karst deposits from southern Tocantins, northern Brazil. The analyzed specimens are assigned to Thrichomys sp., Makalata cf. didelphoides and Proechimys sp. This is the first time that a fossil of Makalata is reported. The Pleistocene record of echimyids from this area is represented by fragmentary remains, which hinders their determination at specific levels. The data reported here contributes to the understanding of the ancient diversity of rodents of this region, evidenced until now in other groups, such as the artiodactyls, cingulates, carnivores, marsupials, and squamate reptiles

Early to late Ediacaran conglomeratic wedges from a complete foreland basin cycle in the southwest São Francisco Craton, Bambuí Group, Brazil

© 2017 Elsevier B.V. Stratigraphic, isotopic, and geochronological data from two late Neoproterozoic-aged conglomerate wedges in the southwest São Francisco craton support the interpretation that the Ediacaran Bambuí Group in east-central Brazil was deposited in a foreland basin. The Samburá Formation forms the base of the Bambuí Group in the southwestern part of the Bambuí basin and was deposited synchronously with the Brasília orogeny. It is interpreted to be a sedimentary product of a retrogradational coastal alluvial fan system deposited in an underfilled flexural foredeep during the early stages of foreland basin development sometime between 630 and 560 Ma. The basal Sete Lagoas Formation carbonates were deposited towards the cratonic margin on the forebulge, which provided an ideal environment for carbonate production. The lateral relationship between the Samburá and Sete Lagoas formations further implies that an unconformity was generated by foreland flexure, and that this unconformity separates an early Ediacaran phase of the foreland basin from a late Ediacaran phase. The Lagoa Formosa Formation was deposited in the latter phase, after peak orogenesis, with a provenance that includes post-orogenic granites and zircons as young as 560 Ma. It records a prograding turbidite fan system in the Lagoa Formosa Formation that was deposited during orogenic unroofing and basin-wide shallowing in a filled stage of the foreland basin. A shift from highly enriched d 13 C values towards global-like carbon isotopes values in carbonates within the Lagoa Formation, in conjunction with the occurrence of banded iron formation, may suggest deposition in a basin with anoxic and ferruginous deep waters in the Bambuí basin in the latest Ediacaran