Search results for "Cyc"
showing 10 items of 11160 documents
Protist predation can select for bacteria with lowered susceptibility to infection by lytic phages
2015
Background: Consumer-resource interactions constitute one of the most common types of interspecific antagonistic interaction. In natural communities, complex species interactions are likely to affect the outcomes of reciprocal co-evolution between consumers and their resource species. Individuals face multiple enemies simultaneously, and consequently they need to adapt to several different types of enemy pressures. In this study, we assessed how protist predation affects the susceptibility of bacterial populations to infection by viral parasites, and whether there is an associated cost of defence on the competitive ability of the bacteria. As a study system we used Serratia marcescens and i…
Doom of the elephant-dependent trees in a Congo tropical forest.
2013
9 pages; International audience; In an evergreen lowland rain forest of the Cuvette Centrale, DR Congo, at the LuiKotale Max-Planck research site, forest elephants (Loxodonta cyclotis) are close to extinction. Between January 2009 and June 2011 we investigated the influence of elephant decline on sustainability of elephant-dispersed tree populations. For this, we explored how trees with the megafaunal syndrome reproduce without seed dispersal by elephants and how does this affect the demography and spatial distribution of these tree species. We studied alternative partners for functional replacement of the elephant. Overall, 18 tree species presenting the megafaunal syndrome were identified…
Seasonal cycle of benthic denitrification and DNRA in the aphotic coastal zone, northern Baltic Sea
2020
Current knowledge on the seasonality of benthic nitrate reduction pathways in the aphotic, density stratified coastal zone of the Baltic Sea is largely based on data from muddy sediments, neglecting the potential contribution of sandy sediments. To gain a more comprehensive understanding of seasonality in this part of the Baltic Sea coast, we measured rates of benthic denitrification, anammox and dissimilatory nitrate reduction to ammonium (DNRA) monthly in the ice-free period of 2016 in both sandy and muddy aphotic sediments, northwestern Gulf of Finland. No anammox was observed. The seasonal cycle of denitrification in both sediment types was related to the hydrography-driven development …
Mediterranean identities - environment, society, culture
2017
The Mediterranean Sea, one of the most complex marine ecosystems, is inhabited by a rich and diverse biota which is disproportionate to its dimensions. It is cur‐ rently affected by different pressures, mainly driven by human activities such as cli‐ mate change and bioinvasions. This Sea, also due to its geographic position (wedged between the temperate climate of central Europe and the arid climate of northern Africa), seems to be one of the regions most susceptible to global climate change. The increased rates of introduction and spread of marine alien species may represent a supplementary stress factor to Mediterranean marine native biota already challenged by climatic abnormalities. The…
Annual cycle of starch content in rhizomes of the forest geophytes Anemone nemorosa and Aegopodium podagraria
1997
Summary Starch contents of rhizomes of Anemone nemorosa L. and Aegopodium podagraria L. were measured enzymatically. The results were compared to the developmental stage determined weekly. Minimum starch contents were measured few weeks after the begin of the growth period, then the starch contents increased during leaf expansion to reach its maximum immediately before the yellowing of the leaves. During the yellowing starch contents did not increase further due to rhizome growth. Anemone nemorosa had a higher starch content than Aegopodium podagraria. This can be explained in context of the different growth strategies of the plants. The first species follows the dominance strategy of growt…
ABP1 Mediates Auxin Inhibition of Clathrin-Dependent Endocytosis in Arabidopsis
2010
SummarySpatial distribution of the plant hormone auxin regulates multiple aspects of plant development. These self-regulating auxin gradients are established by the action of PIN auxin transporters, whose activity is regulated by their constitutive cycling between the plasma membrane and endosomes. Here, we show that auxin signaling by the auxin receptor AUXIN-BINDING PROTEIN 1 (ABP1) inhibits the clathrin-mediated internalization of PIN proteins. ABP1 acts as a positive factor in clathrin recruitment to the plasma membrane, thereby promoting endocytosis. Auxin binding to ABP1 interferes with this action and leads to the inhibition of clathrin-mediated endocytosis. Our study demonstrates th…
Voles and weasels in the boreal Fennoscandian small mammal community : What happens if the least weasel disappears due to climate change?
2019
Climate change, habitat loss and fragmentation are major threats for populations and a challenge for individual behavior, interactions and survival. Predator–prey interactions are modified by climate processes. In the northern latitudes, strong seasonality is changing and the main predicted feature is shortening and instability of winter. Vole populations in the boreal Fennoscandia exhibit multiannual cycles. High amplitude peak numbers of voles and dramatic population lows alternate in 3–5‐year cycles shortening from North to South. One key factor, or driver, promoting the population crash and causing extreme extended lows, is suggested to be predation by the least weasel. We review the ar…
An optimised multi-host trematode life cycle: fishery discards enhance trophic parasite transmission to scavenging birds
2016
Overlapping distributions of hosts and parasites are critical for successful completion of multi-host parasite life cycles and even small environmental changes can impact on the parasite's presence in a host or habitat. The generalist Cardiocephaloides longicollis was used as a model for multi-host trematode life cycles in marine habitats. This parasite was studied to quantify parasite dispersion and transmission dynamics, effects of biological changes and anthropogenic impacts on life cycle completion. We compiled the largest host dataset to date, by analysing 3351 molluscs (24 species), 2108 fish (25 species) and 154 birds (17 species) and analysed the resultant data based on a number of …
Demographic responses of a site-faithful and territorial predator to its fluctuating prey: long-tailed skuas and arctic lemmings.
2014
Summary1. Environmental variability, through interannual variation in food availability or climaticvariables, is usually detrimental to population growth. It can even select for constancy in keylife-history traits, though some exceptions are known. Changes in the level of environmentalvariability are therefore important to predict population growth or life-history evolution.Recently, several cyclic vole and lemming populations have shown large dynamical changesthat might affect the demography or life-histories of rodent predators.2. Skuas constitute an important case study among rodent predators, because of theirstrongly saturating breeding productivity (they lay only two eggs) and high deg…
Diet and habitat use influence Hg and Cd transfer to fish and consequent biomagnification in a highly contaminated area: Augusta Bay (Mediterranean S…
2016
Abstract Total mercury (T-Hg) and cadmium (Cd) were measured in twenty species of fish to study their bioaccumulation patterns and trophodynamics in the Augusta Bay food web. Adult and juvenile fish were caught in 2012 in Priolo Bay, south of the Augusta harbour (Central Mediterranean Sea), which is known for the high trace element and polycyclic aromatic hydrocarbon contamination level. T-Hg concentration was found to significantly increase along δ15N and from pelagic to benthic sedentary fish, revealing a marked influence of trophic position and habitat use (sensu Harmelin 1987) on T-Hg accumulation within ichthyofauna. Cd showed the opposite pattern, in line with the higher trace element…