Search results for "Systematics"
showing 10 items of 6702 documents
New European Discovery of Splachnum pensylvanicum (Bryophyta, Splachnaceae) in Lithuania, with Taxonomic Notes and a Review of Its World Distribution
2021
Splachnum pensylvanicum (Brid.) Grout ex H.A.Crum is recorded for the first time in Lithuania and it is its fourth discovery at a third locality in Europe. It was found for the first time in 2000 in Kamanos mire, the largest peatland complex in the northern part of this East Baltic country. Targeted investigations at this site in 2017 resulted in the discovery of 14 populations and it is apparently the largest and most abundant locality of the species in Europe. Splachnum pensylvanicum is briefly described and illustrated along with some taxonomic notes and a detailed description of its habitat requirements. The global geographical distribution of S. pensylvanicum is reviewed and mapped. It…
NG2-expressing cells in the nervous system: role of the proteoglycan in migration and glial–neuron interaction
2005
The NG2 glycoprotein is a type I membrane protein expressed in the developing and adult central nervous system (CNS) by subpopulations of glia including oligodendroglial precursor cells (OPCs), and in the developing CNS additionally by pericytes. In the mouse CNS, expression of NG2 protein is already observed at embryonic day 13 and peaks between postnatal days 8 and 12. NG2+ cells persist in grey and white matter in adult mouse brain: cells in the developing and adult brain show clear differences in migration, cell-cycle length and lineage restriction. Several groups have provided evidence that subpopulations of NG2+ cells can generate neurons in vivo. Neuronal stimulation in the developin…
Position of Blackbird (Turdus Merula) Nests in Orange Trees
2012
Nest placement affects the risk of predation and determines the microclimate for incubation. We have analysed the nest placement of the blackbird nests and the temperatures at which they are exposed in an orange plantation from Eastern Spain. The data come from a 16.9 ha of an orange plantation. In this plot, nest searching techniques were applied. Nest placement and the temperatures at midday were recorded from a sample of 84 nests. Furthermore, a sample of 16 nests was used to determine the daily variation between 8:00 and 20:00 hours. We measured the nest height, tree height, and distance from the tree centre to the nest, and the length of the longest branch. The temperatures inside the…
The cavity-nest ant Temnothorax crassispinus prefers larger nests
2014
Colonies of the ant Temnothorax crassispinus inhabit mostly cavities in wood and hollow acorns. Typically in the field, nest sites that can be used by the ant are a limited resource. In a field experiment, it was investigated whether the ants prefer a specific size of nest, when different ones are available. In July 2011, a total of 160 artificial nests were placed in a beech-pine forest. Four artificial nests (pieces of wood with volume cavities, ca 415, 605, 730, and 980 mm3, respectively) were located on each square meter of the experimental plot. One year later, shortly before the emergence of new sexuals, the nests were collected. In July 2012, colonies inhabited more frequently bigger…
A Genome-Wide Screen for Interactions Reveals a New Locus on 4p15 Modifying the Effect of Waist-to-Hip Ratio on Total Cholesterol
2011
Recent genome-wide association (GWA) studies described 95 loci controlling serum lipid levels. These common variants explain ∼25% of the heritability of the phenotypes. To date, no unbiased screen for gene–environment interactions for circulating lipids has been reported. We screened for variants that modify the relationship between known epidemiological risk factors and circulating lipid levels in a meta-analysis of genome-wide association (GWA) data from 18 population-based cohorts with European ancestry (maximum N = 32,225). We collected 8 further cohorts (N = 17,102) for replication, and rs6448771 on 4p15 demonstrated genome-wide significant interaction with waist-to-hip-ratio (WHR) on …
Early steps in building the insect brain: neuroblast formation and segmental patterning in the developing brain of different insect species
2003
In insects, morphological, molecular and genetic studies have provided a detailed insight into the ontogenetic processes that shape the ventral nerve cord. On the other hand, owing to its complexity and less obvious segmental composition, the knowledge about the development of the brain is still fragmentary. A promising approach towards gaining insight into fundamental processes underlying brain development is the comparison of embryonic brain development among different insect species. However, so far such comparative analyses are scarce. In this review, we summarize and compare data on the early steps in brain formation in different hemi- and holometabolous insects. We show that basic asp…
Parental effects in a filamentous fungus : Phenotype, fitness and mechanism
2023
AbstractAdaptation to changing environments often requires meaningful phenotypic modifications to match the current conditions. However, obtaining information about the surroundings during an organism’s own lifetime may only permit accommodating relatively late developmental modifications. Therefore, it may be advantageous to rely on inter-generational or trans-generational cues that provide information about the environment as early as possible to allow development along an optimal trajectory. Transfer of information or resources across generations, known as parental effects, is well documented in animals and plants but not in other eukaryotes, such as fungi. Understanding parental effects…
Diversification and community assembly of the world’s largest tropical island
2022
Aim: The species diversity and endemism of tropical biotas are major contributors to global biodiversity, but the factors underlying the formation of these systems remain poorly understood. Location: The world's largest tropical island, New Guinea. Time period: Miocene to present. Major taxa studied: Passerine birds. Methods: We first generated a species-level phylogeny of all native breeding passerine birds to analyse spatial and elevational patterns of species richness, species age and phylogenetic diversity. Second, we used an existing dataset on bill morphology to analyse spatial and elevational patterns of functional diversity. Results: The youngest New Guinean species are principally …
Mapping field-scale spatial patterns of size and activity of the denitrifier community
2009
International audience; There is ample evidence that microbial processes can exhibit large variations in activity on a field scale. However, very little is known about the spatial distribution of the microbial communities mediating these processes. Here we used geostatistical modelling to explore spatial patterns of size and activity of the denitrifying community, a functional guild involved in N-cycling, in a grassland field subjected to different cattle grazing regimes. We observed a non-random distribution pattern of the size of the denitrifier community estimated by quantification of the denitrification genes copy numbers with a macro-scale spatial dependence (6–16 m) and mapped the dis…
Comparative Genomics of Blattabacterium cuenoti: The Frozen Legacy of an Ancient Endosymbiont Genome
2013
Many insect species have established long-term symbiotic relationships with intracellular bacteria. Symbiosis with bacteria has provided insects with novel ecological capabilities, which have allowed them colonize previously unexplored niches. Despite its importance to the understanding of the emergence of biological complexity, the evolution of symbiotic relationships remains hitherto a mystery in evolutionary biology. In this study, we contribute to the investigation of the evolutionary leaps enabled by mutualistic symbioses by sequencing the genome of Blattabacterium cuenoti, primary endosymbiont of the omnivorous cockroach Blatta orientalis, and one of the most ancient symbiotic associa…