Mosaic-like Distribution Research Articles

Convergent evolution revealed by paraphyly and polyphyly of many taxa of oribatid mites: A molecular approach.

A reliable phylogeny is crucial for understanding the evolution and radiation of animal taxa. Phylogenies based on morphological data may be misleading due to frequent convergent evolution of traits-a problem from which molecular phylogenies suffer less. This may be particularly relevant in oribatid mites, an ancient soil animal taxon with more than 11,000 species, where the classification of species into high-ranking taxa such as superfamilies is equivocal. Here, we present a molecular phylogeny of 317 oribatid, 4 astigmatid and 17 endeostigmatid mite species/taxa based on 18S rDNA sequences. We aimed at testing the validity of the 41 superfamilies of oribatid mites recognized by Norton and Behan-Pelletier (in Krantz and Walter, A manual of Acarology,3rd ed., Texas Technical University Press, Lubbock, 2009). The results indicate that 17 of the 41 oribatid mite superfamilies are monophyletic but that 18 superfamilies are paraphyletic or polyphyletic (5 superfamilies were only included with one species and Microzetoidea were not included). Our findings point to the importance of convergent evolution in polyphyletic oribatid mite taxa. Convergent evolution and the old age of mites likely resulted in a mosaic-like distribution of morphological characters impeding phylogenetic reconstructions based on morphology, calling for molecular approaches to improve oribatid mite systematics.

Retyping and molecular pathology diagnosis of dyschromatosis universalis hereditaria.

Dyschromatosis universalis hereditaria (DUH) is characterized by diffuse symmetrically distributed hypopigmented macules mixed with hyperpigmentation. DUH is divided into three types by Online Mendelian inheritance in man (OMIM) that is, DUH1 (OMIM 127500), DUH2 (OMIM 612715) and DUH3 (OMIM 615402) according to the different linkage regions. Although each condition possesses corresponding phenotypic characteristics and the prognosis for each is somewhat different, these disorders are highly overlapped and difficult to differentiate in the clinical setting. Our latest study reveals a novel DUH subtype that presents a mild phenotype of pigmentation anomalies and is named PER3rs772027021 SNP related DUH or DUH4 by us, which make the DUH subtype can be further retyped. Heterozygous distribution or mosaic-like distribution of melanin is a newly discovered pathological features that is uniquely demonstrated in the affected layers of DUH1 and DUH4 patients. In this review, DUH is further divided into four subtypes according the causative genes and their mutational sites, and the mutation regions described in the previous reports. To make an accurate diagnosis, we suggest that Sanger sequencing or the target region sequencing (TRS) to the candidate causative genes related melanogenesis may be the most effective and convenient method of clinical diagnosis or/and prenatal diagnosis for DUH and DUH-like patients. More importantly, heterozygous distribution or mosaic-like distribution of melanin can be utilized for differential diagnosis of DUH. We also investigate the underlying molecular mechanism to form mosaic-like melanin in the affected layers of hyper- and/or hypo-pigmented macules from DUH1 and DUH4 patients. This review provides a molecular and pathological delineation of four types of DUH and aims to establish a concise diagnostic strategy to allow clinical dermatologists to make an accurate diagnosis.

Ribosomal protein SA is a common component of neuronal intranuclear inclusions in polyglutamine diseases and Marinesco bodies.

Neuronal intranuclear inclusions (NIIs) are common key structures in polyglutamine (polyQ) diseases such as Huntington disease (HD), spinocerebellar ataxia type 1 (SCA1), and SCA3. Marinesco bodies (MBs) of dopaminergic neurons in the substantia nigra are also intranuclear structures and arefrequently seen in normal elderly people. Ribosomal dysfunction is closely related to two differential processes; therefore, we aimed to identify the pathological characteristics of ribosomal protein SA (RPSA), a ribosomal protein, in both states. To this end, we evaluated the autopsy findings in four patients with HD, two SCA3, and five normal elderly cases (NCs). Immunohistochemical studies demonstrated that both NIIs and MBs contain RPSA. In polyQ diseases, RPSA was co-localized with polyQ aggregations, and 3D-reconstructed images revealed their mosaic-like distribution. Assessments of the organization of RPSA and p62 in NIIs showed that RPSA was more localized toward the center than p62 and that this unique organization was more evident in the MBs. Immunoblotting of the temporal cortices revealed that the nuclear fraction of HD patients contained more RPSA than that of NCs. In conclusion, our study revealed that RPSA is a common component of both NIIs and MBs, indicating that a similar mechanism contributes to the formation of polyQ NIIs and MBs.

Multimodal high-resolution nano-DESI MSI and immunofluorescence imaging reveal molecular signatures of skeletal muscle fiber types.

The skeletal muscle is a highly heterogeneous tissue comprised of different fiber types with varying contractile and metabolic properties. The complexity in the analysis of skeletal muscle fibers associated with their small size (30-50 μm) and mosaic-like distribution across the tissue tnecessitates the use of high-resolution imaging to differentiate between fiber types. Herein, we use a multimodal approach to characterize the chemical composition of skeletal fibers in a limb muscle, the gastrocnemius. Specifically, we combine high-resolution nanospray desorption electrospray ionization (nano-DESI) mass spectrometry imaging (MSI) with immunofluorescence (IF)-based fiber type identification. Computational image registration and segmentation approaches are used to integrate the information obtained with both techniques. Our results indicate that the transition between oxidative and glycolytic fibers is associated with shallow chemical gradients (<2.5 fold change in signals). Interestingly, we did not find any fiber type-specific molecule. We hypothesize that these findings might be linked to muscle plasticity thereby facilitating a switch in the metabolic properties of fibers in response to different conditions such as exercise and diet, among others. Despite the shallow chemical gradients, cardiolipins (CLs), acylcarnitines (CAR), monoglycerides (MGs), fatty acids, highly polyunsaturated phospholipids, and oxidized phospholipids, were identified as molecular signatures of oxidative metabolism. In contrast, histidine-related compounds were found as molecular signatures of glycolytic fibers. Additionally, the presence of highly polyunsaturated acyl chains in phospholipids was found in oxidative fibers whereas more saturated acyl chains in phospholipids were found in glycolytic fibers which suggests an effect of the membrane fluidity on the metabolic properties of skeletal myofibers.

Differential impacts of alternate primary producers on carbon cycling.

Disturbance impacts the spatial distribution of primary producers, which can have cascading effects on ecosystem function. The lower-intertidal zone on the rocky shores of the Pacific Northwest is one such place where wave energy creates a mosaic-like distribution between two assemblages: surfgrass (Phyllospadix scouleri) meadows and macroalgal forests dominated by kelp. We simulated wave disturbance by experimentally removing patches of surfgrass monocultures, resulting in a macroalgal assemblage with increased diversity, biomass, and net primary productivity in the following year. Although surfgrass had a higher C:N compared to macroalgal assemblages, macroalgal assemblages achieved a higher biomass, fixed carbon at a faster rate, and released more dissolved organic carbon (DOC) during photosynthesis. Thus, despite similar standing amounts of carbon, macroalgal assemblages have increased carbon turnover-from fixation to DOC release. Comparative photophysiology indicated that surfgrasses have a competitive advantage over other macrophytes at low light levels, allowing them to persist when disturbance is reduced. Unexpectedly, disturbance in this system increased the potential for carbon sequestration when surfgrass monocultures were replaced by diverse macroalgae.

Spatial heterogeneity in genetic diversity and composition of bacterial symbionts in a single host species population

Revealing genetic diversity in a root nodulation symbiosis under field conditions is critical to understand the formation of ecological communities of organisms associated with hosts and the nitrogen cycle in natural ecosystems. However, our knowledge of the genetic diversity of bacterial mutualists on a local scale is still poor because of the assumption that the genetic diversity of mutualistic bacteria is constrained by their hosts. We thoroughly investigated the genetic diversity of Frankia in a local forest stand. We collected root nodules from 213 Alnus hirsuta seedlings covering the spatial range of the continuous population, which means that Alnus individuals occurred in a relatively homogeneous distribution in a continuous forest. Then, a phylogenetic and diversity analysis was performed for the nifD-K IGS region, including global Frankia sequences from Alnus hosts. The genetic diversity of Frankia detected even on a local scale measured as high as that shown by previous studies conducted on local and regional scales. Moreover, a genetic structure analysis revealed a spatially mosaic-like distribution of genetic variation in Frankia despite the small spatial scale. The genetic diversity and composition of bacterial mutualists are heterogeneous on a local scale. Our findings demonstrate that genetically different bacterial symbionts simultaneously interact with a single host population and interaction partnerships spatially vary. The standing variation could produce dynamic ecological and evolutionary outcomes in a heterogeneous forest ecosystem.

Coordinated Intervention of Microglial and Müller Cells in Light-Induced Retinal Degeneration.

PurposeTo analyze the role of microglial and Müller cells in the formation of rings of photoreceptor degeneration caused by phototoxicity.MethodsTwo-month-old Sprague-Dawley rats were exposed to light and processed 1, 2, or 3 months later. Retinas were dissected as whole-mounts, immunodetected for microglial cells, Müller cells, and S- and L/M-cones and analyzed using fluorescence, thunder imaging, and confocal microscopy. Cone populations were automatically counted and isodensity maps constructed to document cone topography.ResultsPhototoxicity causes a significant progressive loss of S- and L/M-cones of up to 68% and 44%, respectively, at 3 months after light exposure (ALE). One month ALE, we observed rings of cone degeneration in the photosensitive area of the superior retina. Two and 3 months ALE, these rings had extended to the central and inferior retina. Within the rings of cone degeneration, there were degenerating cones, often activated microglial cells, and numerous radially oriented processes of Müller cells that showed increased expression of intermediate filaments. Between 1 and 3 months ALE, the rings coalesced, and at the same time the microglial cells resumed a mosaic-like distribution, and there was a decrease of Müller cell gliosis at the areas devoid of cones.ConclusionsLight-induced photoreceptor degeneration proceeds with rings of cone degeneration, as observed in inherited retinal degenerations in which cone death is secondary to rod degeneration. The spatiotemporal relationship of cone death microglial cell activation and Müller cell gliosis within the rings of cone degeneration suggests that, although both glial cells are involved in the formation of the rings, they may have coordinated actions and, while microglial cells may be more involved in photoreceptor phagocytosis, Müller cells may be more involved in cone and microglial cell migration, retinal remodeling and glial seal formation.

The demographic and agricultural development of the Kokand oasis during the Russian Imperial era: nomad immigration and cotton monoculture

ABSTRACTThis study investigates oasis expansion in the precolonial period and agricultural evolution in the colonial period using village-level statistics from the early twentieth century. This survey illustrates that the Kokand oasis in the Ferghana Valley initially appeared in the central part, where the Sart population settled by the seventeenth century. In the eighteenth and nineteenth centuries, the Uzbek and Karakalpak tribes migrated to the valley peripheries, while the Kyrgyz semi-nomads settled in the alluvial fan. It is not surprising that such a migratory process created a mosaic-like ethnic distribution. Furthermore, this study suggests that the pattern coincided with a variety of agricultural practices, and presents two contrasting models of cotton monoculture under the Russian Empire. The main area occupied by the Sarts presents a general model of canal-irrigated cotton planting in Central Asia, while the Karakalpaks’ cotton planting using groundwater in the periphery suggests multiple courses of nomad sedentarization.

Outcrop analog for an oolitic carbonate ramp reservoir: A scale-dependent geologic modeling approach based on stratigraphic hierarchy

Considerable effort has been devoted to the development of simulation algorithms for facies modeling, whereas a discussion of how to combine those techniques has not existed. The integration of multiple geologic data into a three-dimensional model, which requires the combination of simulation techniques, is yet a current challenge for reservoir modeling. This article presents a thought process that guides the acquisition and modeling of geologic data at various scales. Our work is based on outcrop data collected from a Jurassic carbonate ramp located in the High Atlas mountain range of Morocco. The study window is 1 km (0.6 mi) wide and 100 m (328.1 ft) thick. We describe and model the spatial and hierarchical arrangement of carbonate bodies spanning from largest to smallest: (1) stacking pattern of high-frequency depositional sequences, (2) facies association, and (3) lithofacies. Five sequence boundaries were modeled using differential global position system mapping and light detection and ranging data. The surface-based model shows a low-angle profile with modest paleotopographic relief at the inner-to-middle ramp transition. Facies associations were populated using truncated Gaussian simulation to preserve ordered trends between the inner, middle, and outer ramps. At the lithofacies scale, field observations and statistical analysis show a mosaiclike distribution that was simulated using a fully stochastic approach with sequential indicator simulation. This study observes that the use of one single simulation technique is unlikely to correctly model the natural patterns and variability of carbonate rocks. The selection and implementation of different techniques customized for each level of the stratigraphic hierarchy will provide the essential computing flexibility to model carbonate settings. This study demonstrates that a scale-dependent modeling approach should be a common procedure when building subsurface and outcrop models.

Upper Mississippian (Lower Carboniferous) carbonate stratigraphy and syndepositional faulting reveal likely Ouachita flexural forebulge effects, eastern Kentucky, U.S.A.

Stratigraphic analysis of late Middle to early Late Mississippian (Early Carboniferous; late Meramecian–early Chesterian) carbonates in east-central and northeastern Kentucky, U.S.A., shows six unconformity-bound sequences. The earliest, late Meramecian, St. Louis sequence shows a relatively uniform distribution and a typical eastward Appalachian gradient along the ENE-trending outcrop belt on the western margin of the Appalachian Basin. However, abrupt uplift and exposure of deeper water St. Louis deposits, indicated by erosional thinning and well-developed exposure features, at the Meramecian–Chesterian transition signal inception of regional early Chesterian uplift that intensively altered the nature and distribution of the five overlying early Chesterian carbonate sequences. Uplift was related to the syndepositional reactivation of WNW-trending basement faults that broke up the St. Louis platform and generated a mosaic-like distribution of the overlying five sequences due to structurally related erosional incision and paleoslope change to the southwest. These early Chesterian events coincide with a major phase of northeast-directed Ouachita Orogeny on the southern margin of Laurussia and concomitant forebulge migration to the ENE. Modeling of regional stress distribution, as well as timing and location during bulge migration, strongly indicate that a migrating Ouachita bulge reactivated basement structures and generated the noted stratigraphic anomalies in eastern Kentucky and nearby areas. The likelihood of low-amplitude flexural waves, like the Ouachita bulge, migrating across areas where they were not previously considered, has major implications for understanding structural, stratigraphic, and eustatic anomalies in supposedly stable cratonic areas far removed from active tectonism.

Heterozygote manifestations in X-chromosomal ectodermal dysplasia

About 60-70 % of the heterozygotes of X-linked hypohidrotic ectodermal dysplasia (XLHED) show some clinical manifestations of the disease. Dental abnormalities are key diagnostic features and can be best evaluated at a young age. Compared to controls, carriers have a significantly higher frequency of agenesis of permanent teeth with persistence of deciduous teeth, small teeth resulting in gaps between the teeth, and peg-shaped teeth. Whole saliva flow seems to be reduced in carriers, whereas concentrations of most inorganic salivary constituents and total protein are higher than in controls. Craniofacial morphology of carriers shows some subtle deviations such as short and retrognatic maxilla, protruding lips, and a shorter total facial height compared to controls, findings that could be explained in part by hypodontia. Mild hypotrichosis and mild hypohidrosis are two further commonly seen carrier signs. No correlation has been found so far between the type of mutations, the patients’ phenotypes and disease severity. The mosaic-like distribution of normal and abnormal skin along the Blaschko lines is a typical consequence of the clonal inactivation of the X-chromosomes. While carriers with a highly skewed X-chromosome inactivation pattern may show pronounced clinical features due to the unequal expression of the two alleles (‘functional hemizygosity’), no correlation has been found between the severity of clinical symptoms and X-chromosome inactivation in leukocytes of carriers. Sporadic cases of males with XLHED and autosomal recessive HED (arHED) cannot be distinguished clinically. In contrast to heterozygotes of XLHED, who frequently show mild involvement, heterozygous parents of patients with arHED show no features of the disorder. However, because of the highly variable expression of XLHED in carriers, phenotypic assessment may result both in underdetection and false-positive diagnosis.

Evolutionary classification: A case study on the diverse plant genus Ranunculus L. (Ranunculaceae)

Evolutionary classification attempts to integrate information on shared ancestry, evolutionary process and phenetic information into the taxonomic concept. Here we exemplify this concept on the monophyletic, species-rich and cosmopolitan plant genus Ranunculus. Previous classifications have rendered almost all traditional sections as polyphyletic, and a modern revision based on phylogenetic principles was so far lacking. Maximum parsimony and Bayesian inference analysis of a combined nuclear (ITS of nrDNA) and plastid DNA dataset (matK/trnK, and psbJ–petA) provided a phylogenetic framework for the genus with nine well-supported subclades. Neighbor Net analysis revealed a reticulate data structure within two subclades with frequent polyploidy and/or hybridization. Character evolution was studied by McClade reconstructions of morphological data mapped on to the molecular tree topology. Morphological characters show a mosaic-like distribution, but express several shared states congruent to molecular clades. A total evidence approach (TE) based on the combined morphological and molecular dataset suggests a subdivision of Ranunculus into a paraphyletic, temperate to arctic group of five subclades (subg. Auricomus), and a temperate to subtropical clade with four subclades (subg. Ranunculus). Infrageneric classification of two subgenera and 17 sections is based on both monophyly s.l. as evident from TE and a minimum of shared morphological characters. Six subclades have shared morphological or karyological features (sects. Auricomus, Flammula, Oreophili, Polyanthemos, Ranunculus, Thora, and Trisecti). One subclade was subdivided into three smaller clades according to morphological data (sects. Epirotes, Leucoranunculus, Ranuncella, Aconitifolii). In the case of reticulate evolution and uncertain ancestry we accept well-supported genetic clusters with shared morphological features, as revealed by Neighbor Net analysis (sections Batrachium, Hecatonia, Pseudadonis). Character evolution connected to ecological shifts characterizes the paraphyletic section Ranunculastrum, the holophyletic section Euromontani (sect. nov.), and the monotypic sect. Echinella. The information content of our classification is compared to alternative concepts.

Nuclei of Tsuga canadensis: Role of Flavanols in Chromatin Organization

Needle primordia of Tsuga canadensis (hemlock) arising from flank meristems of a shoot apex, form cell lineages consisting of four or eight cells. Within a recently established lineage there is striking uniformity in the pattern of nuclear flavanols. This fact points to an identical transcriptional expression of these flavanols during cell cycling. However two lineages, even if located close together within the same meristem, can be very different in the expression of both cell shape and nuclear flavanol pattern, indicating that epigenetic positional signals are operating in a collective specification of cell lineage development. There is a wide range of nuclear flavanol patterning from a mosaic-like distribution in an activated cell type to a homogenous appearance in silenced cell types. Single cells deriving from lineages are desynchronized because they underlie a signaling network at a higher tissue level which results in stronger epigenetic modifications of their nuclear flavanols. As an extreme case of epigenetic modulation, transient drought conditions caused a drastic reduction of nuclear flavanols. Upon treatment with sucrose or cytokinin, these nuclear flavanols could be fully restored. Analytical determination of the flavanols revealed 3.4 mg/g DW for newly sprouting needles and 19.6 mg/g DW for anthers during meiosis. The roughly 6-fold difference in flavanols is apparently a reflection of the highly diverging organogenetic processes. Collectively, the studies provide strong evidence for combinatorial interplay between cell fate and nuclear flavanols.

Phylogeographic structure of brown trout Salmo trutta in Britain and Ireland: glacial refugia, postglacial colonization and origins of sympatric populations

The phylogeographical structure of brown trout Salmo trutta in Britain and Ireland was studied using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of four mitochondrial DNA segments (16S/ND1, ND5/6, COXIII/ND5 and ND5/12S). Analysis of 3636 individuals from 83 sites-morphotypes revealed a total of 25 haplotypes. These haplotypes were nested in seven two-step clades. Although there was a clear geographical patterning to the occurrence of derived clades, admixture among ancestral clades was extensive throughout the studied area. A relevant feature of the data was that some populations contained mixtures of highly divergent clades. This type II phylogeographic pattern is uncommon in nature. Clade intermixing is likely to have taken place during earlier interglacials as well as since the Last Glacial Maximum. The anadromous life history of many S. trutta populations has probably also contributed to clade mixing. Based on the data presented here and published data, postglacial colonization of Britain and Ireland most likely involved S. trutta from at least five potential glacial refuges. Probable locations for such refugia were: south of England-western France, east of the Baltic Sea, western Ireland, Celtic Sea and North Sea. Ferox S. trutta, as defined by their longevity, late maturation and piscivory, exhibited a strong association with a particular clade indicating that they share a common ancestor. Current evidence indicates that the Lough Melvin gillaroo S. trutta and sonaghen S. trutta sympatric types diverged prior to colonization of Lough Melvin and, although limited gene flow has occurred since secondary contact, they have remained largely reproductively isolated due to inlet and outlet river spawning segregation. Gillaroo S. trutta may reflect descendents of a previously more widespread lineage that has declined due to habitat alterations particularly affecting outlet rivers. The mosaic-like distribution of mtDNA lineages means that conservation prioritization in Britain and Ireland should be based on the biological characteristics of local populations rather than solely on evolutionary lineages.

Oral bacterial biofilms – history in progress

Oral bacterial biofilms – history in progress

Compartmented flow at the Bátaapáti site in Hungary

Integration of hydrogeological and geological data into a conceptual model is critical for site investigation programs, since this model is the basis for hydrogeological modeling and for engineering. In the Hungarian Radioactive Waste Disposal Investigation Program, several methods have been used to characterize the potential host rock (granite) at the Bataapati site for a repository for low and intermediate level radioactive waste. Hydrogeological data acquisition revealed some characteristic aspects of the site. One of the most important is the presence of extensive rock deformation zones (faults) with low hydraulic conductivity, which strongly reduce the direct hydraulic communication between adjacent blocks of rock (compartmentalization). This characteristic of the rock mass results in a mosaic-like distribution of rock compartments, each with an almost constant hydraulic head. Within the compartments, hydraulic tests have shown that transmissivity is strongly scale dependent: the larger the scale, the higher the measured transmissivity. The extensive highly transmissive zones cause very low hydraulic gradients within each block, thus the transport processes are strongly influenced by the low or average transmissivity zones and the rock matrix.

LIVE BENTHIC FORAMINIFERAL ASSEMBLAGES AT THE PACIFIC CONTINENTAL MARGIN OF COSTA RICA AND NICARAGUA

Living (rose-Bengal-stained) foraminifera were investigated from the continental margin off the Pacific Coast of Costa Rica and Nicaragua. Assemblages from seven stations, including mounds and mud volcanoes, were compared in terms of foraminiferal density, distribution patterns, diversity and species composition and related to environmental factors (satellite chlorophyll a imagery, organic carbon content in the sediment, available oxygen data, particle grain sizes). Sediments from mud volcanoes and mounds did not show direct influence of seepage. Highest foraminiferal densities were found on the slope off Nicaragua. The lowest foraminiferal densities were found in the north off Costa Rica where the smooth Cocos Plate segment subducts beneath the Caribbean Plate. Intermediate values were counted in the southern investigated area, where the down-going plate has a rough topography. Observed foraminiferal densities did not always correspond to chlorophyll a imagery or measured organic carbon content in the sediment, suggesting a possible influence of time-limited food supply, lateral transport of sinking organic material and local variability in the investigated area. In total, 187 species were recognized, distributed across the seven stations, which all showed high diversity. Foraminiferal associations contained many Buliminida, pointing to low-oxygen concentrations at the sediment-water interface. Some taxa indicated a possible bathymetric or regional limitation. The assemblage composition varied among the stations to such a degree that no commonalities were identified, based on results from multivariate analysis. This was also the case for samples originating from mounds and mud volcanoes, which did not show any outstandingly different assemblages, meaning that no characteristic foraminiferal assemblage could be used to identify these areas. This mosaic-like distribution pointed to a large degree of habitat heterogeneity in the relatively small area; the habitat heterogeneity could explain the overall high diversity of benthic foraminifera in the region.

Genome‐wide association to fine‐scale ecological heterogeneity within a continuous population ofBiscutella laevigata(Brassicaceae)

Gene flow, drift and selection can be detected through different signatures across the genome and the landscape. Genetic discontinuities along with their correlation to environmental features can be used to tease out isolation-by-distance and isolation-by-time from processes related to selection. Using spatial statistics (spatial autocorrelation methods, canonical correspondence analysis and partial Mantel tests) dealing with genome-wide amplified fragment length polymorphism (AFLP) under unlikely Hardy-Weinberg assumptions, this study investigates 124 individuals within a continuous population of the autopolyploid Biscutella laevigata (Brassicaceae). Fine-scale spatial genetic structure was strong and the mosaic-like distribution of AFLP genotypes was consistently associated with habitat factors, even when controlled for geographical distances. The use of multivariate analyses enabled separation of the factors responsible for the repartition of the genetic variance and revealed a composite effect of isolation by distance, phenological divergence and local adaptation to habitats characterised by different solar radiation regimes. These results suggest that the immigrant inviability barrier facilitated the maintenance of adapted subpopulations to distinct environmental conditions at the local scale.

Hand movement distribution in the motor cortex: the influence of a concurrent task and motor imagery

The aim of this work was to study the relevance of the primary motor cortex (M1) for motor functions different to the simple execution of motor orders. The M1 activity during the performance with individual fingers of a simple motor task (tonic flexion), a motor task that includes a complex motor computation but not motor execution (motor imagery), and a motor task that involves both the computation and execution of movements (phasic movement) was evaluated by functional magnetic resonance imaging (fMRI). The possible influence of other cortical tasks on the M1 activation induced by finger movements was assessed by evaluating the effect of a distracting concurrent task (numeric calculation). Data show that both the dimension of the area activated and the intensity of response were higher during motor planning than during motor execution. There is a mosaic-like distribution for motor-planning M1 functions, with the movement of individual fingers being controlled from several M1 loci. The concurrent mental-task induces a rapid functional reconfiguration of M1, adding M1 subsets to motor programming but excluding others. Present data support the involvement of the M1 in more than just simple motor execution, showing broader and more intense modifications during motor tasks not accompanied by movements (motor imagery) than during the execution of simple motor acts (tonic flexion).

Angiogenesis and phenotypic alteration of alveolar capillary endothelium in areas of neoplastic cell spread in primary lung adenocarcinoma.

Normal alveolar capillary endothelium is quiescent in nature and displays anticoagulant thrombomodulin (TM) on its surface. The cytoplasms of these endothelial cells are ultrastructurally non-fenestrated type, and they barely express von Willebrand factor (vWf). Alveolar fibrosis is accompanied by a capillary endothelium reactive for vWf, and a loss of TM expression. In primary lung adenocarcinoma, neovascularization occurs in association with alveolar fibrosis. In order to study basic factors related to angiogenesis and phenotypic changes of the capillaries located in tumor-bearing alveolar walls, we examined 37 primary lung adenocarcinomas with electron microscopy and confocal laser scanning microscopy with antibodies for TM, vWf, vascular endothelial growth factor (VEGF), and its receptors (KDR and Flt-1), and proliferating markers (Ki-67/proliferating cell nuclear antigen). Tissues microdissected specifically from alveolar walls were used for reverse transcription-polymerase chain reaction (RT-PCR) to assess expressions of mRNA isoforms of VEGF and its receptors. New capillary branching was found by ultrastructural study in the alveolar walls in 12% of the patients. Nuclei of the capillary endothelial cells were reactive for proliferating cell markers. Endothelial fenestrae were developed in 65% of the patients, TM reactivity was lost in the alveolar capillaries, and their cell cytoplasms obtained a reactivity for vWf through a transitional mosaic-like distribution pattern of both antigens. Besides cytoplasmic VEGF expression in neoplastic cells, tumor-bearing alveolar walls showed significant expression of mRNA of VEGF165 and KDR. These findings imply that angiogenesis and phenotypic changes of the alveolar capillaries are closely related to a higher expression of tumor-associated VEGF165 and of KDR in the alveolar walls in primary lung adenocarcinoma.