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991.
Caroline E. R. Lehmann Catherine L. Parr 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2016,371(1703)
Tropical grassy biomes (TGBs) are changing rapidly the world over through a coalescence of high rates of land-use change, global change and altered disturbance regimes that maintain the ecosystem structure and function of these biomes. Our theme issue brings together the latest research examining the characterization, complex ecology, drivers of change, and human use and ecosystem services of TGBs. Recent advances in ecology and evolution have facilitated a new perspective on these biomes. However, there continues to be controversies over their classification and state dynamics that demonstrate critical data and knowledge gaps in our quantitative understanding of these geographically dispersed regions. We highlight an urgent need to improve ecological understanding in order to effectively predict the sensitivity and resilience of TGBs under future scenarios of global change. With human reliance on TGBs increasing and their propensity for change, ecological and evolutionary understanding of these biomes is central to the dual goals of sustaining their ecological integrity and the diverse services these landscapes provide to millions of people.This article is part of the themed issue ‘Tropical grassy biomes: linking ecology, human use and conservation’. 相似文献
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Methodological improvements now allow routine analyses of highly degraded DNA samples as found in museum specimens. Using these methods could be useful in studying such groups as rodents of the genus Gerbillus for which i) the taxonomy is still highly debated, ii) collection of fresh specimens may prove difficult. Here we address precise taxonomic questions using a small portion of the cytochrome b gene obtained from 45 dry skin/skull museum samples (from 1913 to 1974) originating from two African and three Asian countries. The specimens were labelled Gerbillus
gerbillus, Gerbillus
andersoni, Gerbillus
nanus, Gerbillus
amoenus, Gerbillus
perpallidus and Gerbillus
pyramidum, and molecular results mostly confirmed these assignations. The close relationship between Gerbillus
nanus (Asian origin) and Gerbillus
amoenus (African origin) confirmed that they represent vicariant sibling species which differentiated in allopatry on either side of the Red Sea. In the closely related Gerbillus
perpallidus and Gerbillus
pyramidum, specimens considered as belonging to one Gerbillus
pyramidum subspecies (Gerbillus
pyramidum
floweri) appeared closer to Gerbillus
perpallidus suggesting that they (Gerbillus
pyramidum
floweri and Gerbillus
perpallidus) may represent a unique species, distributed on both sides of the Nile River, for which the correct name should be Gerbillus
floweri. Furthermore, the three other Gerbillus
pyramidum subspecies grouped together with no apparent genetic structure suggesting that they may not yet represent genetically differentiated lineages. This study confirms the importance of using these methods on museum samples, which can open new perspectives in this particular group as well as in other groups of interest. 相似文献
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995.
Mitochondrial dysfunction in a transgenic mouse model expressing human amyloid precursor protein (APP) with the Arctic mutation 下载免费PDF全文
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Caroline Leuchtenberger Renata Sousa-Lima Carolina Ribas William E. Magnusson Guilherme Mourão 《Bioacoustics.》2016,25(3):279-291
Acoustic variation can convey identity information, facilitate social interactions among individuals and may be useful in identifying sex and group affiliation of senders. Giant otters live in highly cohesive groups with exclusive territories along water bodies defended by the entire group by means of acoustic and chemical signals. Snorts are harsh alarm calls, emitted in threat contexts, which commonly elicit the cohesion and the alert behaviour of the members of the group. The aim of this study was to determine whether giant otter snorts have potential to be used for individual discrimination. We tested this hypothesis by verifying if the acoustic characteristics of snorts vary between two study areas, among social groups and individuals, and between males and females. Snort acoustic variables did not differ significantly among study areas, but varied significantly among groups, individuals and between sexes, with higher discrimination between sexes. The frequency of formants (F1–F5) and formant dispersion (DF) potentially allow identity coding among groups, individuals and sexes. The stronger sex discrimination of snorts may be related to information on body size carried by formant frequencies and dispersion, indicating acoustic sexual dimorphism in giant otters. Acoustic differences among groups and individuals are more likely learned, since we did not find evidence for a genetic signal encoded in the snort variables measured. We conclude that the snorts carry information that could be used for individual or group recognition. 相似文献
999.
Ronivaldo Rodrigues da Silva Tatiane Beltramini Souto Tássio Brito de Oliveira Lilian Caroline Gonçalves de Oliveira Daniel Karcher Maria Aparecida Juliano Luiz Juliano Arthur H. C. de Oliveira André Rodrigues Jose C. Rosa Hamilton Cabral 《Journal of industrial microbiology & biotechnology》2016,43(8):1059-1069
In this study, we detail the specificity of an aspartic peptidase from Rhizomucor miehei and evaluate the effects of this peptidase on clotting milk using the peptide sequence of k-casein (Abz-LSFMAIQ-EDDnp) and milk powder. Molecular mass of the peptidase was estimated at 37 kDa, and optimum activity was achieved at pH 5.5 and 55 °C. The peptidase was stable at pH values ranging from 3 to 5 and temperatures of up 45 °C for 60 min. Dramatic reductions in proteolytic activity were observed with exposure to sodium dodecyl sulfate, and aluminum and copper (II) chloride. Peptidase was inhibited by pepstatin A, and mass spectrometry analysis identified four peptide fragments (TWSISYGDGSSASGILAK, ASNGGGGEYIFGGYDSTK, GSLTTVPIDNSR, and GWWGITVDRA), similar to rhizopuspepsin. The analysis of catalytic specificity showed that the coagulant activity of the peptidase was higher than the proteolytic activity and that there was a preference for aromatic, basic, and nonpolar amino acids, particularly methionine, with specific cleavage of the peptide bond between phenylalanine and methionine. Thus, this peptidase may function as an important alternative enzyme in milk clotting during the preparation of cheese. 相似文献
1000.