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Grazing by the isopod Idotea baltica induces chemical defenses in the brown seaweed Fucus vesiculosus. A combination of a 33 day induction experiment, feeding choice assays and functional genomic analyses was used to investigate temporal defense patterns and to correlate changes in palatability to changes in gene expression. Despite permanent grazing, seaweed palatability varied over time. Controls were significantly more consumed than grazed pieces only after 18 and 27 days of grazing. Relative to controls, 562/402 genes were up-/down-regulated in seaweed pieces that were grazed for 18 days, i.e. when defense induction was detected. Reprogramming of the regulative expression orchestra (translation, transcription), up-regulation of genes involved in lipid and carbohydrate metabolism, intracellular trafficking, defense and stress response, as well as downregulation of photosynthesis was found in grazed seaweed. These findings indicate short-term temporal variation in defenses and that modified gene expression patterns arise at the same time when grazed seaweed pieces show reduced palatability. Several genes with putative defensive functions and cellular processes potentially involved in defence, such as reallocation of resources from primary to secondary metabolism, were revealed

We examine the marginal effects of decentralized public health spending by incorporating estimates of behavioural responses to changes in public health spending through benefit incidence analysis. The analysis is based on a panel dataset of 207 Indonesian districts over a 4-year period from 2001 to 2004. We show that district-level public health spending is largely driven by central government transfers, with an elasticity of public health spending with respect to district revenues of around 0.9. We find a positive effect of public health spending on utilization of outpatient care in the public sector for the poorest two quartiles. We find no evidence that public expenditures crowd out utilization of private services or household health spending. Our analysis suggests that increased public health spending improves targeting to the poor, as behavioural changes in public health care utilization are pro-poor. Nonetheless, most of the benefits of the additional spending accrued to existing users of services, as initial utilization shares outweigh the behavioural responses.

ZusammenfassungDer kosmopolitische Polychaet Scoloplos armiger (O. F. Müller, 1776) besitzt in der Nordsee zwei verschiedene Fortpflanzungsweisen. Zusätzlich zu der allgemein bekannten, direkten, holobenthischen Entwicklung aus Laichbeeren, die regelmäßig im Gezeitenbereich zu finden sind, wurden vor Helgoland pelagische Larven gefunden. In Voruntersuchungen zu dieser Arbeit wurden pelagische Larven von S. armiger ebenfalls im Wattenmeer vor der Insel Sylt entdeckt, wo auch Laichbeeren sehr häufig vorkommen. Die anfängliche Hypothese, dass sublitorale S. armiger pelagische Larven produzieren, wurde in Zuchtexperimenten im Labor bestätigt. Damit war gleichzeitig bewiesen, dass vor Sylt räumlich getrennte Quellen der beiden Fortpflanzungsmodi vorhanden sind.Um den taxonomischen Status von Scoloplos armiger abzuschätzen, wurden unterschiedliche Ansätze und Methoden angewandt. Die Ergebnisse zeigen, dass es sich bei S. armiger vor Sylt um zwei sympatrische Geschwisterarten handelt, für die eine Bezeichnung als S. armiger 'Type I' für die im Gezeitenbereich lebende Art, und 'Type S' für die Art aus sublitoralen Bereichen, vorgeschlagen wird. Morphologische Vergleiche zwischen frühen benthischen Stadien sublitoraler und eulitoraler Juvenilen ergaben signifikant längere Analcirren bei sublitoralen Tieren. Genetische Untersuchungen (RAPD- und AFLP-PCR) von 3 eulitoralen and 4 sublitoralen Populationen ergaben signifikant unterschiedliche Genpools in den Habitaten (sublitoral/ eulitoral), d.h. die genetische Divergenz war nicht abhängig von räumlicher Distanz sondern von der Unterscheidung im Habitattyp. Kreuzungsexperimente zeigen eine reproduktive Isolation von eu- und sublitoralen S. armiger. Paare von Männchen und Weibchen aus verschiedenen Habitaten produzierten keine Nachkommen, während Paare aus dem selben Habitat lebendige Larven hervorbrachten. Pelagische Larven entstanden nur von Paaren mit sublitoralen Männchen und sublitoralen Weibchen, wobei 2 von 14 sublitoralen Weibchen Laichbeeren produzierten. Ansonsten war die Produktion von Laichbeeren immer von der eulitoralen Herkunft der Weibchen abhängig.Als eine Ursache für eine reproduktive Isolation wurde eine unterschiedliche Spermatozoenmorphologie als Befruchtungsbarriere ausgemacht. Spermatozoen von eulitoralen Männchen hatten doppelt so lange Köpfe und signifikant kürzere Flagellen als die von sublitoralen Männchen. Eu- und sublitorale S. armiger unterscheiden sich außerdem in ökologischen Charakteren. Sublitorale S. armiger waren weniger tolerant gegen Hypoxie und Sulfid als eulitorale Tiere. Die gemessene Sulfidexposition war im Sublitoral 5-10 mal niedriger als im Eulitoral. Langzeituntersuchungen zum jahreszeitlichen Auftreten von Laichbeeren und pelagischen Larven zeigen eine Überlappung im Frühjahr, während nur pelagische Larven ein zweites Vorkommen im Herbst aufweisen. Dieses Herbstvorkommen und eine Quantifizierung von pelagischen S. armiger im Wattenmeer wird erstmalig beschrieben. Hohe Gesamt-abundanzen von pelagischen Larven im Wattenmeer legen eine Neubewertung der Populationsdynamiken von S. armiger nahe.Abschließend wird diskutiert, wie die heutige Situation von zwei S. armiger Geschwisterarten, die sympatrisch, aber mit unterschiedlicher Habitatpräferenz vorkommen, entstanden sein könnte. Dies resultiert in drei Szenarien einer Artbildung in S. armiger. Am Schluss steht ein Ausblick auf Artbildungsprozesse im Meer.AbstractFor the common, cosmopolitan polychaete Scoloplos armiger (O. F. Müller, 1776) two developmental modes exist in the North Sea region. In addition to direct, holobenthic development out of egg cocoons, well-known to occur on intertidal flats, pelagic larvae were found around the off-shore island of Helgoland. In this study a preliminary survey revealed that pelagic larvae are also present around the Wadden Sea island of Sylt where egg cocoons are common on intertidal flats. The initial hypothesis of that subtidal S. armiger produce pelagic larvae was confirmed by laboratory breeding experiments, prooving that around the Island of Sylt spatially separated sources of two developmental modes exist adjacent to each other. The basic question of this study, whether an intertidal and subtidal species of Scoloplos armiger exist in the North Sea, was proposed.Different approaches and methods were used to assess the taxonomic status of Scoloplos armiger. All results indicate that there are two sympatric sibling species in S. armiger, 'Type I' living in the intertidal zone and 'Type S' living subtidally. Morphological comparison of early benthic stages of intertidal and subtidal juveniles revealed significantly longer anal cirri in subtidal specimens. Genetic study (RAPD- and AFLP-PCR) on 3 intertidal and 4 subtidal populations revealed that genetic divergence is not related to distance but to the intertidal/ subtidal division. Cross breeding experiments show that intertidal and subtidal populations are reproductively isolated. Couples with males and females from different habitats had no offspring while mates from the same habitat produced viable larvae. Pelagic larvae occurred only in couples with subtidal females and subtidal males while egg cocoons were also produced by two out of fourteen subtidal females. Apart from that, production of egg cocoons is determined by female origin from the intertidal zone.Spermatozoa of intertidal males have heads twice as long and a significantly shorter flagellum than those from subtidal males. It is suggested that deviating sperm morphology may cause the reproductive breakdown at the fertilization stage. Intertidal and subtidal S. armiger furthermore exhibit ecological divergence. Tolerance against sulphide and hypoxia were both lower in subtidal than in intertidal specimens. This correlates with a 5 to 10-fold lower sulphide concentration at subtidal compared to intertidal sites. Egg cocoon and pelagic larval spawning period recorded over six years overlap temporally in spring. Pelagic larvae are released in an additional autumn spawning which is absent for egg cocoons and was unknown till now. High overall abundances of pelagic larvae in the Wadden Sea in this first quantitative record of pelagic S. armiger larvae suggest reassessments of S. armiger population dynamic models.It is discussed how the present-day situation with distinct, sympatric species occurring in geographic overlap while exhibiting segregation by habitat may have evolved, resulting in three speciation scenarios for S. armiger. In the end an outlook on speciation processes in the sea is given.

The ecology of nemertean predators in marine ecosystems is reviewed. Nemerteans occur in most marine environments although usually in low abundances. Some species, particularly in intertidal habitats, may reach locally high densities. During specific time periods appropriate for hunting, nemerteans roam about in search of prey. Upon receiving a stimulus (usually chemical cues), many nemertean species actively pursue their prey and follow them into their dwellings or in their tracks. Other species (many hoplonemerteans) adopt a sit-and-wait strategy, awaiting prey items in strategic locations. Nemerteans possess potent neurotoxins, killing even highly mobile prey species within a few seconds and within the activity range of its attacker. Most nemertean species prey on live marine invertebrates, but some also gather on recently dead organisms to feed on them. Heteronemerteans preferentially feed on polychaetes, while most hoplonemerteans prey on small crustaceans. The species examined to date show strong preferences for selected prey species, but will attack a variety of alternative prey organisms when deprived of their favourite species. Ontogenetic changes in prey selection appear to occur, but no further information about e.g. size selection is available. Feeding rates as revealed from short-term laboratory experiments range on the order of 1-5 prey items d-1. These values apparently are overestimates, since long-term experiments report substantially lower values (0.05 - 0.3 prey items d-1). Nemerteans have been reported to exert a strong impact on the population size of their prey organisms through their predation activity. Considering low predation rates, these effects may primarily be a result of indirect and additive interactions. We propose future investigations on these interactive effects in combination with other predators. Another main avenue of nemertean ecological research appears to be their role in highly structured habitats such as intertidal rocky shore habitats and coral reef environments.

In the European Wadden Sea, the nemertine Tetrastemma melanocephalum occurs together with its prey, the amphipod Corophium arenarium in the upper intertidal zone. T. melanocephalum leaves the sediment when the tide has receded and captures C. arenarium in its U-shaped burrow. Highest abundances of T. melanocephalum on the sediment surface were found on summer evenings, two to four hours after high tide, when just a thin film of water was left on the flats. Laboratory Y-maze experiments indicated that gradients of substances produced by C. arenarium in this film of water play a role in tracking the prey. In the field, T. melanocephalum appeared in significantly higher numbers on experimental high density patches of C. arenarium. The amphipod in turn is able to recognize the nemertine. In aquarium experiments significantly more amphipods escaped from the sediment into the water column when the predator was present. In the field, both predator and prey showed a high mobility by drifting in tidal waters. Benthic abundance maxima of T. melanocephalum and C. arenarium usually did not coincide spatially. It is assumed that the nemertines avoid tidal flats that dry out quickly leaving too little time for prey capture. T. melanocephalum is not able to dig into the sediment but lives in burrows of Nereis diversicolor. The abundance of this polychaete was inversely related to C. arenarium, presenting a dilemma for T. melanocephalum: the spatial overlap of food and accommodation was rather small.

Ten young volunteer subjects were given diets in which the main fat component was either butter fat or the fat of a dietetic margarine containing close to 40 per cent of linoleic acid.All the subjects received the butter diet through a period of 3 weeks. Immediately thereafter, eight of the subjects received the margarine diet for one or two consecutive periods of 3 weeks (± 1 day), whereas two of the subjects continued on the butter diet for two additional periods of 3 weeks each.Before the experiment and after each dietary period, duodenal bile was collected (after cholecystokinin injection) and analyzed with respect to dry matter, pH, cholesterol, lipid-soluble phosphorus, bile acids, the individual phospholipids and the fatty acid pattern of bile lecithin.The bile produced under the influence of the butter diet consistently contained close to twenty or twenty odd per cent of linoleic acid in the total fatty acids of the lecithin, whereas the corresponding figure for the bile produced under the influen...

The "segmentation clock" is thought to coordinate sequential segmentation of the body axis in vertebrate embryos. This clock comprises a multicellular genetic network of synchronized oscillators, coupled by intercellular Delta-Notch signaling. How this synchrony is established and how its loss determines the position of segmentation defects in Delta and Notch mutants are unknown. We analyzed the clock's synchrony dynamics by varying strength and timing of Notch coupling in zebrafish embryos with techniques for quantitative perturbation of gene function. We developed a physical theory based on coupled phase oscillators explaining the observed onset and rescue of segmentation defects, the clock's robustness against developmental noise, and a critical point beyond which synchrony decays. We conclude that synchrony among these genetic oscillators can be established by simultaneous initiation and self-organization and that the segmentation defect position is determined by the difference between coupling strength and noise.