Resistenz der Meeresalgen gegen sichtbares Licht und gegen kurzwellige UV-Strahlen

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Zur Frage der Salzpermeabilität bei Braunalgen

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How rapidly do self‐compatible populations evolve selfing? Mating system estimation within recently evolved self‐compatible populations of Azorean Tolpis succulenta (Asteraceae)

Genome‐wide genotyping and Bayesian inference method (BORICE) were employed to estimate outcrossing rates and paternity in two small plant populations of Tolpis succulenta (Asteraceae) on Graciosa island in the Azores. These two known extant populations of T. succulenta on Graciosa have recently evolved self‐compatibility. Despite the expectation that selfing would occur at an appreciable rate (self‐incompatible populations of the same species show low but nonzero selfing), high outcrossing was found in progeny arrays from maternal plants in both populations. This is inconsistent with an immediate transition to high selfing following the breakdown of a genetic incompatibility system. This finding is surprising given the small population sizes and the recent colonization of an island from self‐incompatible colonists of T. succulenta from another island in the Azores, and a potential paucity of pollinators, all factors selecting for selfing through reproductive assurance. The self‐compatible lineage(s) likely have high inbreeding depression (ID) that effectively halts the evolution of increased selfing, but this remains to be determined. Like their progeny, all maternal plants in both populations are fully outbred, which is consistent with but not proof of high ID. High multiple paternity was found in both populations, which may be due in part to the abundant pollinators observed during the flowering season.     

An inordinate fondness for Mecopteriformia

What is the Largest animal taxon? The most famous answer to this question has been given by Haldane who coined the phrase that ‘the Creator has an inordinate fondness for beetles’. Although much cited, this statement has never been tested. Other experts have suggested other candidates for the largest animal taxon, all of which included the beetles as a subordinate group. I here outline a novel phylogenetic‐comparative method that can address the question in a testable way. The result of applying the algorithm to the Metazoa is astonishing: the largest animal taxon is neither beetles nor a taxon super‐ or subordinated to beetles, but the Mecopteriformia.     

Physical Health Problems and Environmental Challenges Influence Balancing Behaviour in Laying Hens

With rising public concern for animal welfare, many major food chains and restaurants are changing their policies, strictly buying their eggs from non-cage producers. However, with the additional space in these cage-free systems to perform natural behaviours and movements comes the risk of injury. We evaluated the ability to maintain balance in adult laying hens with health problems (footpad dermatitis, keel damage, poor wing feather cover; n = 15) using a series of environmental challenges and compared such abilities with those of healthy birds (n = 5). Environmental challenges consisted of visual and spatial constraints, created using a head mask, perch obstacles, and static and swaying perch states. We hypothesized that perch movement, environmental challenges, and diminished physical health would negatively impact perching performance demonstrated as balance (as measured by time spent on perch and by number of falls of the perch) and would require more exaggerated correctional movements. We measured perching stability whereby each bird underwent eight 30-second trials on a static and swaying perch: with and without disrupted vision (head mask), with and without space limitations (obstacles) and combinations thereof. Video recordings (600 Hz) and a three-axis accelerometer/gyroscope (100 Hz) were used to measure the number of jumps/falls, latencies to leave the perch, as well as magnitude and direction of both linear and rotational balance-correcting movements. Laying hens with and without physical health problems, in both challenged and unchallenged environments, managed to perch and remain off the ground. We attribute this capacity to our training of the birds. Environmental challenges and physical state had an effect on the use of accelerations and rotations to stabilize themselves on a perch. Birds with physical health problems performed a higher frequency of rotational corrections to keep the body centered over the perch, whereas, for both health categories, environmental challenges required more intense and variable movement corrections. Collectively, these results provide novel empirical support for the effectiveness of training, and highlight that overcrowding, visual constraints, and poor physical health all reduce perching performance.     

Role of the GNOM gene in Arabidopsis apical-basal patterning – From mutant phenotype to cellular mechanism of protein action

How the apical-basal axis of polarity is established in embryogenesis is still a mystery in plant development. This axis appeared specifically compromised by mutations in the Arabidopsis GNOM gene. Surprisingly, GNOM encodes an ARF guanine-nucleotide exchange factor (ARF-GEF) that regulates the formation of vesicles in membrane trafficking. In-depth functional analysis of GNOM and its closest relative, GNOM-LIKE 1 (GNL1), has provided a mechanistic explanation for the development-specific role of a seemingly mundane trafficking regulator. The current model proposes that GNOM is specifically involved in the endosomal recycling of the auxin-efflux carrier PIN1 to the basal plasma membrane in provascular cells, which in turn is required for the accumulation of the plant hormone auxin at the future root pole through polar auxin transport. Thus, the analysis of GNOM highlights the importance of cell-biological processes for a mechanistic understanding of development.     

Modelling secondary succession of neotropical mangroves: Causes and consequences of growth reduction in pioneer species

Mangrove forest structure is the result of interactions between species responses to abiotic stress factors, disturbance, dispersal and competition. The combination of abiotic conditions and disturbance history may determine the growth potential of the species, whereas dispersal, competition and external or biogenic changes in abiotic conditions may tune their succession. Even in forests with only a few species, this set of factors can create multiple species compositions. For example, pure stands of the mangrove Laguncularia are common in newly colonized areas, but they may evolve into mixed stands dominated by Rhizophora or Avicennia. We demonstrate such an evolution with a field study of mangroves established in abandoned rice fields. We use an individual-based simulation model to understand how species-dependent dispersal, growth rate and shade tolerance lead to the observed patterns in horizontal and vertical forest structure. We find that the initially dominating species will be gradually replaced in the canopy. This alteration cannot be explained exclusively by shade tolerance of the succeeding species. Rather, it is essential to assume that the height growth rate of the pioneer species slows down relative to those of the later species. A decrease in nutrient availability may be responsible for these relative changes in the growth rates of different species.     

Whole genome analysis of the marine Bacteroidetes'Gramella forsetii' reveals adaptations to degradation of polymeric organic matter

Members of the Bacteroidetes, formerly known as the Cytophaga-Flavobacteria-Bacteroides (CFB) phylum, are among the major taxa of marine heterotrophic bacterioplankton frequently found on macroscopic organic matter particles (marine snow). In addition, they have been shown to also represent a significant part of free-living microbial assemblages in nutrient-rich microenvironments. Their abundance and distribution pattern in combination with enzymatic activity studies has led to the notion that organisms of this group are specialists for degradation of high molecular weight compounds in both the dissolved and particulate fraction of the marine organic matter pool, implying a major role of Bacteroidetes in the marine carbon cycle. Despite their ecological importance, comprehensive molecular data on organisms of this group have been scarce so far. Here we report on the first whole genome analysis of a marine Bacteroidetes representative, 'Gramella forsetii' KT0803. Functional analysis of the predicted proteome disclosed several traits which in joint consideration suggest a clear adaptation of this marine Bacteroidetes representative to the degradation of high molecular weight organic matter, such as a substantial suite of genes encoding hydrolytic enzymes, a predicted preference for polymeric carbon sources and a distinct capability for surface adhesion.     

Report of the Working Group on Animal Distress in the Laboratory

Finding ways to minimize pain and distress in research animals is a continuing goal in the laboratory animal research field. Pain and distress, however, are not synonymous, and measures that alleviate one may not affect the other. Here, the authors provide a summary of a meeting held in February 2004 that focused on distress in laboratory animals. They discuss the difficulties associated with defining 'distress,' propose methods to aid in recognizing and alleviating distressful conditions, and provide recommendations for animal research conduct and oversight that would minimize distress experienced by laboratory animals.