• MeSH
• balistokardiografie MeSH
• kardiologie MeSH
• Publikační typ
• kongresy MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• kardiologie

Observation and analysis of cancer cell behaviour in 3D environment is essential for full understanding of the mechanisms of cancer cell invasion. However, label-free imaging of live cells in 3D conditions is optically more challenging than in 2D. Quantitative phase imaging provided by coherence controlled holographic microscopy produces images with enhanced information compared to ordinary light microscopy and, due to inherent coherence gate effect, enables observation of live cancer cells' activity even in scattering milieu such as the 3D collagen matrix. Exploiting the dynamic phase differences method, we for the first time describe dynamics of differences in cell mass distribution in 3D migrating mesenchymal and amoeboid cancer cells, and also demonstrate that certain features are shared by both invasion modes. We found that amoeboid fibrosarcoma cells' membrane blebbing is enhanced upon constriction and is also occasionally present in mesenchymally invading cells around constricted nuclei. Further, we demonstrate that both leading protrusions and leading pseudopods of invading fibrosarcoma cells are defined by higher cell mass density. In addition, we directly document bundling of collagen fibres by protrusions of mesenchymal fibrosarcoma cells. Thus, such a non-invasive microscopy offers a novel insight into cellular events during 3D invasion.

• MeSH
• buněčná membrána metabolismus   MeSH
• buněčné kultury metody   MeSH
• fibrosarkom diagnostické zobrazování   patologie   MeSH
• holografie přístrojové vybavení   metody   MeSH
• intravitální mikroskopie přístrojové vybavení   metody   MeSH
• invazivní růst nádoru diagnostické zobrazování   patologie   MeSH
• kolagen metabolismus   MeSH
• lidé MeSH
• nádorové buněčné linie MeSH
• pohyb buněk * MeSH
• pseudopodia metabolismus   MeSH
• zobrazování trojrozměrné přístrojové vybavení   metody   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Biological invasions are a global issue with far-reaching consequences for single species, communities and whole ecosystems. Our understanding of modes and mechanisms of biological invasions requires knowledge of the genetic processes associated with successful invasions. In many instances, this information is particularly difficult to obtain as the initial phases of the invasion process often pass unnoticed and we rely on inferences from contemporary population genetic data. Here, we combined historic information with the genetic analysis of resting eggs to reconstruct the invasion of Daphnia pulicaria into Lower Lake Constance (LLC) in the 1970s from the resting egg bank in the sediments. We identified the invader as 'European D. pulicaria' originating from meso- and eutrophic lowland lakes and ponds in Central Europe. The founding population was characterized by extremely low genetic variation in the resting egg bank that increased considerably over time. Furthermore, strong evidence for selfing and/or biparental inbreeding was found during the initial phase of the invasion, followed by a drop of selfing rate to low levels in subsequent decades. Moreover, the increase in genetic variation was most pronounced during early stages of the invasion, suggesting additional introductions during this period. Our study highlights that genetic data covering the entire invasion process from its beginning can be crucial to accurately reconstruct the invasion history of a species. We show that propagule banks can preserve such information enabling the study of population genetic dynamics and sources of genetic variation in successful invasive populations.

• MeSH
• buněčné jádro genetika   MeSH
• Daphnia genetika   MeSH
• frekvence genu MeSH
• fylogeneze MeSH
• genetická variace MeSH
• genetické markery MeSH
• genotyp MeSH
• geologické sedimenty MeSH
• inbreeding MeSH
• jezera MeSH
• mikrosatelitní repetice MeSH
• mitochondriální DNA genetika   MeSH
• modely genetické MeSH
• molekulární sekvence - údaje MeSH
• ovum * MeSH
• populační dynamika MeSH
• populační genetika * MeSH
• sekvenční analýza DNA MeSH
• zavlečené druhy MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Německo MeSH
• Švýcarsko MeSH

Boom-bust dynamics - the rise of a population to outbreak levels, followed by a dramatic decline - have been associated with biological invasions and offered as a reason not to manage troublesome invaders. However, boom-bust dynamics rarely have been critically defined, analyzed, or interpreted. Here, we define boom-bust dynamics and provide specific suggestions for improving the application of the boom-bust concept. Boom-bust dynamics can arise from many causes, some closely associated with invasions, but others occurring across a wide range of ecological settings, especially when environmental conditions are changing rapidly. As a result, it is difficult to infer cause or predict future trajectories merely by observing the dynamic. We use tests with simulated data to show that a common metric for detecting and describing boom-bust dynamics, decline from an observed peak to a subsequent trough, tends to severely overestimate the frequency and severity of busts, and should be used cautiously if at all. We review and test other metrics that are better suited to describe boom-bust dynamics. Understanding the frequency and importance of boom-bust dynamics requires empirical studies of large, representative, long-term data sets that use clear definitions of boom-bust, appropriate analytical methods, and careful interpretations.

• MeSH
• ekologie * MeSH
• populační dynamika MeSH
• zavlečené druhy * MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

BACKGROUND: Despite the increasing number of studies attempting to model population growth in various organisms, we still know relatively little about the population dynamics of long-lived species that reproduce only in the later stages of their life cycle, such as trees. Predictions of the dynamics of these species are, however, urgently needed for planning management actions when species are either endangered or invasive. In long-lived species, a single management intervention may have consequences for several decades, and detailed knowledge of long-term performance can therefore elucidate possible outcomes during the management planning phase. METHODOLOGY AND PRINCIPAL FINDINGS: We studied the population dynamics of an invasive tree species, Pinus strobus, in three habitat types represented by their position along the elevation gradient occupied by the species. In agreement with previous studies on the population dynamics of long-lived perennials, our results show that the survival of the largest trees exhibits the highest elasticity in all of the studied habitats. In contrast, life table response experiments (LTRE) analysis showed that different stages contribute the most to population growth rates in different habitats, with generative reproduction being more important in lower slopes and valley bottoms and survival being more important on rock tops and upper slopes. CONCLUSIONS: The results indicate that P. strobus exhibits different growth strategies in different habitats that result in similar population growth rates. We propose that this plasticity in growth strategies is a key factor in the invasion success of the white pine. In all of the investigated habitats, the population growth rates are above 1, indicating that the population of the species is still increasing and has the ability to spread and occupy a wide range of habitats.

• MeSH
• borovice růst a vývoj   MeSH
• ekosystém * MeSH
• populační dynamika MeSH
• populační růst * MeSH
• zavlečené druhy * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Švýcarsko MeSH

Understanding the mechanisms that affect invasion success of alien species is an important prerequisite for the effective management of present and future aliens. To gain insight into this matter we asked the following questions: Are the geographical patterns of species distributions in urban floras different for native compared with alien plant species? Does the introduction of alien species contribute to the homogenization of urban floras? We used a Mantel test on Jaccard dissimilarity matrices of 30 urban floras across the British Isles, Italy and central Europe to compare the spatial distribution of native species with four classes of alien species: archaeophytes, all neophytes, non-invasive neophytes, and invasive neophytes. Archaeophytes and neophytes are species that were introduced into Europe before and after 1500 AD, respectively. To analyze the homogenizing effect of alien species on the native urban floras, we tested for differences in the average dissimilarity of individual cities from their group centroid in ordination space. Our results show that the compositional patterns of native and alien species seem to respond to the same environmental drivers, such that all four classes of alien species were significantly related to native species across urban floras. In this framework, alien species may have an impact on biogeographic patterns of urban floras in ways that reflect their history of introduction and expansion: archaeophytes and invasive neophytes tended to homogenize, while non-invasive neophytes tended to differentiate urban floras.

• MeSH
• biologické modely MeSH
• druhová specificita MeSH
• ekosystém * MeSH
• fyziologie rostlin MeSH
• Magnoliopsida klasifikace   fyziologie   MeSH
• počítačová simulace MeSH
• populační dynamika MeSH
• rostliny klasifikace   MeSH
• velkoměsta * MeSH
• zavlečené druhy * MeSH
• zeměpis MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH
• velkoměsta * MeSH

Tumor cell invasion is the most critical step of metastasis. Determination of the mode of invasion within the particular tumor is critical for effective cancer treatment. Protease-independent amoeboid mode of invasion has been described in carcinoma cells and more recently in sarcoma cells on treatment with protease inhibitors. To analyze invasive behavior, we compared highly metastatic sarcoma cells with parental nonmetastatic cells. The metastatic cells exhibited a functional up-regulation of Rho/ROCK signaling and, similarly to carcinoma cells, an amoeboid mode of invasion. Using confocal and traction force microscopy, we showed that an up-regulation of Rho/ROCK signaling leads to increased cytoskeletal dynamics, myosin light chain localization, and increased tractions at the leading edge of the cells and that all of these contributed to increased cell invasiveness in a three-dimensional collagen matrix. We conclude that cells of mesenchymal origin can use the amoeboid nonmesenchymal mode of invasion as their primary invading mechanism and show the dependence of ROCK-mediated amoeboid mode of invasion on the increased capacity of cells to generate force.

• MeSH
• aktiny metabolismus   MeSH
• buněčná adheze fyziologie   MeSH
• čipová analýza proteinů MeSH
• cytoskelet metabolismus   patologie   MeSH
• faktory depolymerizující aktin metabolismus   MeSH
• financování organizované MeSH
• fluorescenční mikroskopie MeSH
• fosforylace MeSH
• invazivní růst nádoru MeSH
• kinázy asociované s rho genetika   metabolismus   MeSH
• kolagen metabolismus   MeSH
• krysa rodu rattus MeSH
• kultivované buňky MeSH
• lehké řetězce myosinu metabolismus   MeSH
• Lim-kinasy genetika   metabolismus   MeSH
• magnetismus MeSH
• matrixová metaloproteinasa 2 metabolismus   MeSH
• mezenchymální kmenové buňky metabolismus   patologie   MeSH
• pohyb buněk fyziologie   MeSH
• rho proteiny vázající GTP genetika   metabolismus   MeSH
• sarkom metabolismus   patologie   MeSH
• upregulace MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH

• Publikační typ
• abstrakty MeSH

Anticipating how epidemics will spread across landscapes requires understanding host dispersal events that are notoriously difficult to measure. Here, we contrast host and virus genetic signatures to resolve the spatiotemporal dynamics underlying geographic expansions of vampire bat rabies virus (VBRV) in Peru. Phylogenetic analysis revealed recent viral spread between populations that, according to extreme geographic structure in maternally inherited host mitochondrial DNA, appeared completely isolated. In contrast, greater population connectivity in biparentally inherited nuclear microsatellites explained the historical limits of invasions, suggesting that dispersing male bats spread VBRV between genetically isolated female populations. Host nuclear DNA further indicated unanticipated gene flow through the Andes mountains connecting the VBRV-free Pacific coast to the VBRV-endemic Amazon rainforest. By combining Bayesian phylogeography with landscape resistance models, we projected invasion routes through northern Peru that were validated by real-time livestock rabies mortality data. The first outbreaks of VBRV on the Pacific coast of South America could occur by June 2020, which would have serious implications for agriculture, wildlife conservation, and human health. Our results show that combining host and pathogen genetic data can identify sex biases in pathogen spatial spread, which may be a widespread but underappreciated phenomenon, and demonstrate that genetic forecasting can aid preparedness for impending viral invasions.

• MeSH
• Bayesova věta MeSH
• biologická evoluce * MeSH
• Chiroptera virologie   MeSH
• genom virový MeSH
• interakce hostitele a patogenu * MeSH
• mikrosatelitní repetice genetika   MeSH
• roční období MeSH
• typy dědičnosti genetika   MeSH
• virus vztekliny genetika   MeSH
• vzteklina epidemiologie   MeSH
• zeměpis MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH
• Geografické názvy
• Peru epidemiologie   MeSH

In infectious disease epidemiology the basic reproductive ratio, R0, is defined as the average number of new infections caused by a single infected individual in a fully susceptible population. Many models describing competition for hosts between non-interacting pathogen strains in an infinite population lead to the conclusion that selection favors invasion of new strains if and only if they have higher R0 values than the resident. Here we demonstrate that this picture fails in finite populations. Using a simple stochastic SIS model, we show that in general there is no analogous optimization principle. We find that successive invasions may in some cases lead to strains that infect a smaller fraction of the host population, and that mutually invasible pathogen strains exist. In the limit of weak selection we demonstrate that an optimization principle does exist, although it differs from R0 maximization. For strains with very large R0, we derive an expression for this local fitness function and use it to establish a lower bound for the error caused by neglecting stochastic effects. Furthermore, we apply this weak selection limit to investigate the selection dynamics in the presence of a trade-off between the virulence and the transmission rate of a pathogen.

• MeSH
• biologická evoluce * MeSH
• hustota populace * MeSH
• infekční nemoci epidemiologie   patofyziologie   MeSH
• interakce hostitele a patogenu MeSH
• lidé MeSH
• logistické modely * MeSH
• počítačová simulace MeSH
• selekce (genetika) * MeSH
• virulence MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH