Effects of Bacillus Subtilis-Zinc on Rats with Congenital Zinc Deficiency

Biological Trace Element Research - This study investigated the effects of dietary supplementation of Bacillus subtilis-zinc on growth rates of the body and organs, nutrient utilization, microbial...     

Demographic History,Population Structure,and Local Adaptation in Alpine Populations of Cardamine impatiens and Cardamine resedifolia

Species evolution depends on numerous and distinct forces, including demography and natural selection. For example, local adaptation and population structure affect the evolutionary history of species living along environmental clines. This is particularly relevant in plants, which are often characterized by limited dispersal ability and the need to respond to abiotic and biotic stress factors specific to the local environment. Here we study the demographic history and the possible existence of local adaptation in two related species of Brassicaceae, Cardamine impatiens and Cardamine resedifolia, which occupy separate habitats along the elevation gradient. Previous genome-wide analyses revealed the occurrence of distinct selective pressures in the two species, with genes involved in cold response evolving particularly fast in C. resedifolia. In this study we surveyed patterns of molecular evolution and genetic variability in a set of 19 genes, including neutral and candidate genes involved in cold response, across 10 populations each of C. resedifolia and C. impatiens from the Italian Alps (Trentino). We inferred the population structure and demographic history of the two species, and tested the occurrence of signatures of local adaptation in these genes. The results indicate that, despite a slightly higher population differentiation in C. resedifolia than in C. impatiens, both species are only weakly structured and that populations sampled at high altitude experience less gene flow than low-altitude ones. None of the genes showed signatures of positive selection, suggesting that they do not seem to play relevant roles in the current evolutionary processes of adaptation to alpine environments of these species.     

Development of COS genes as universally amplifiable markers for phylogenetic reconstructions of closely related plant species

With the aim of developing widely applicable gene markers for phylogenetic reconstructions at low taxonomic level, we tested the low copy nuclear Conserved Ortholog Set (COS) genes. Most of the 15 genes tested provided good amplification efficiency (as compared with rbcL) from a set of 67 representative angiosperm families. Nine selected COS markers were further characterized at both intra‐ and interfamilial level on a test set, including 25 species representative of 15 different families. While four of the COS led to incongruent results, the remaining five improved the phylogenetic reconstructions of closely related species as illustrated in the case of Orobanchaceae species. They were found to be highly informative in phylogenetic reconstruction of congeneric species, where introns provide a higher proportion of parsimony informative sites in comparison with traditional phylogenetic markers such as ITS and matK. At higher phylogenetic distance, where only coding regions could be aligned, the polymorphism levels of the COS ranged between those of ndhF and matK. On the basis of these results, the success rate in developing universally amplifiable low copy nuclear markers based on COS genes is about 30%. We report the successful development of five pCOS that, together with a few other well characterized genes, such as Rpb2 and GbssI, can be considered the closest approximation to low‐copy “universally” amplifiable markers for phylogeny in plants at present. The possible pitfalls of universally amplifiable COS marker development and their range of applicability at different taxonomic levels in comparison with traditional phylogenetic molecular markers are discussed. © The Willi Hennig Society 2008.     

Rates of evolution in stress-related genes are associated with habitat preference in two <Emphasis Type="Italic">Cardamine</Emphasis> lineages

Background  

Elucidating the selective and neutral forces underlying molecular evolution is fundamental to understanding the genetic basis of adaptation. Plants have evolved a suite of adaptive responses to cope with variable environmental conditions, but relatively little is known about which genes are involved in such responses. Here we studied molecular evolution on a genome-wide scale in two species of Cardamine with distinct habitat preferences: C. resedifolia, found at high altitudes, and C. impatiens, found at low altitudes. Our analyses focussed on genes that are involved in stress responses to two factors that differentiate the high- and low-altitude habitats, namely temperature and irradiation.     

Plastome organization and evolution of chloroplast genes in Cardamine species adapted to contrasting habitats

Background

Plastid genomes, also known as plastomes, are shaped by the selective forces acting on the fundamental cellular functions they code for and thus they are expected to preserve signatures of the adaptive path undertaken by different plant species during evolution. To identify molecular signatures of positive selection associated to adaptation to contrasting ecological niches, we sequenced with Solexa technology the plastomes of two congeneric Brassicaceae species with different habitat preference, Cardamine resedifolia and Cardamine impatiens.

Results

Following in-depth characterization of plastome organization, repeat patterns and gene space, the comparison of the newly sequenced plastomes between each other and with 15 fully sequenced Brassicaceae plastomes publically available in GenBank uncovered dynamic variation of the IR boundaries in the Cardamine lineage. We further detected signatures of positive selection in ten of the 75 protein-coding genes of the examined plastomes, identifying a range of chloroplast functions putatively involved in adaptive processes within the family. For instance, the three residues found to be under positive selection in RUBISCO could possibly be involved in the modulation of RUBISCO aggregation/activation and enzymatic specificty in Brassicaceae. In addition, our results points to differential evolutionary rates in Cardamine plastomes.

Conclusions

Overall our results support the existence of wider signatures of positive selection in the plastome of C. resedifolia, possibly as a consequence of adaptation to high altitude environments. We further provide a first characterization of the selective patterns shaping the Brassicaceae plastomes, which could help elucidate the driving forces underlying adaptation and evolution in this important plant family.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-015-1498-0) contains supplementary material, which is available to authorized users.     

Applying support vector regression analysis on grip force level-related corticomuscular coherence

Voluntary motor performance is the result of cortical commands driving muscle actions. Corticomuscular coherence can be used to examine the functional coupling or communication between human brain and muscles. To investigate the effects of grip force level on corticomuscular coherence in an accessory muscle, this study proposed an expanded support vector regression (ESVR) algorithm to quantify the coherence between electroencephalogram (EEG) from sensorimotor cortex and surface electromyogram (EMG) from brachioradialis in upper limb. A measure called coherence proportion was introduced to compare the corticomuscular coherence in the alpha (7–15Hz), beta (15–30Hz) and gamma (30–45Hz) band at 25 % maximum grip force (MGF) and 75 % MGF. Results show that ESVR could reduce the influence of deflected signals and summarize the overall behavior of multiple coherence curves. Coherence proportion is more sensitive to grip force level than coherence area. The significantly higher corticomuscular coherence occurred in the alpha (p?p?p?相似文献   

High-throughput screening for in planta characterization of VOC biosynthetic genes by PTR-ToF-MS

Journal of Plant Research - Functional characterization of plant volatile organic compound (VOC) biosynthetic genes and elucidation of the biological function of their products often involve the...