UDP-Glucose: Sterol Glucosyltransferase and a Steryl Glucoside Acyltransferase Activity in Amyloplast Membranes from Potato Tubers

Envelope membranes were isolated from potato tuber amyloplastby a discontinuous sucrose density gradient and high speed centrifugation.These membranes catalyzed the transfer of [¹⁴C]glucose fromUDP-[¹⁴C]glucose to endogenous sterol acceptors and, in turn,catalyzed the esterification of steryl glucosides with fattyacids from an endogenous acyl donor. The synthesis of sterylglucosides was stimulated in the presence of Triton. X-100,while formation of acyl steryl glucosides was inhibited by thedetergent. However, in the presence of an added sterol acceptorand Triton X-100, the inhibition of acyl steryl glucoside synthesiswas overcome by the addition of phosphatidylethanolamine. Theenzyme involved in steryl glucoside formation was solubilizedby treatment of the envelope membranes with 0.3% Triton X-100.The solubilized enzyme had an almost absolute requirement forsterol acceptors. Key words: Solanum tuberosum, Sterol glucosylation, Steryl glucoside acylation, Amyloplast membrane     

Nest orientation and hatching success of Black Kites Milvus migrans in Spain

An analysis of the orientation of 182 nest sites of the Black Kite Milvus migrans in two areas in south and central Spain found that orientations toward the east were preferred. In southern Spain an analysis of the relationship between nest orientation and hatching success showed that success was lower among the nests located in non-preferred orientations, with some inter-annual variation. The tendency to orientate nests toward the east was greater among the early nesting pairs and the effect that the orientation had on the hatching success was also greater than in late nesting pairs. The data suggest that rainfall and prevailing winds were the main factors conditioning nest orientation.     

Australia's marine biogeography revisited: Back to the future?

The recognition of broad biogeographic provinces provides an important framework for ecological and conservation biological research. Marine biologists have long recognized distinct biogeographic provinces in southern Australia, primarily on the basis of qualitative differences in intertidal species assemblages. Here we provide an a priori test for these traditional eastern (Peronian), western (Flindersian) and south‐eastern (Maugean) provinces. Specifically, we analyse distributional data for approximately 1500 algal species using the newly available Australian Virtual Herbarium, an online database of herbarium specimens. Our quantitative algal analyses across southern Australia identify three distinct biogeographic assemblages, consistent with traditional qualitative provinces. We argue that these broad provinces provide a highly effective framework for understanding and managing Australia's marine biodiversity. In particular, biogeographic provinces provide a regional framework for integrating the ongoing discovery of biological variation at finer scales. More broadly therefore we recommend that biologists undertake quantitative analyses to test provincial biogeographic boundaries around the globe.     

A rare case of interspecific hybridization in the tracheophone suboscines: Chestnut-naped Antpitta Grallaria nuchalis × Chestnut-crowned Antpitta G. ruficapilla in a fragmented Andean landscape

Based on analyses of variation in plumage, morphometrics, vocalizations, and mitochondrial and nuclear DNA sequences, we document the occurrence of interspecific hybridization between a Chestnut-naped Antpitta Grallaria nuchalis and a Chestnut-crowned Antpitta G. ruficapilla in a high-elevation forest fragment in the Cordillera Central of the Andes of Colombia. One hybrid individual was collected and at least two were recorded singing. The hybrid specimen exhibits a combination of phenotypic traits that exclude other species of antpittas as potential parents, and its vocalizations combine elements of songs of both of its parental species. Genetic analyses demonstrate that the hybrid has G. nuchalis mitochondrial DNA and mixed nuclear DNA with copies corresponding to G. nuchalis and G. ruficapilla alleles, demonstrating that the female parent was G. nuchalis. Hybridization is considered extremely rare in most groups of suboscine passerines, but it may be facilitated when populations are decimated as a consequence of deforestation and habitat fragmentation.