The round goby (Neogobius melanostomus) in the Gulf of Gdańsk – a species introduction into the Baltic Sea

In recent years, information concerning the awareness of organisms accidentally introduced into the Baltic Sea has substantially improved. Non-indigenous Estuarine and Marine Organisms (NEMO's) are hazardous for the Baltic ecosystem. Currently, about one hundred species are identified as accidentally or intentionally introduced into the Baltic Sea. Ballast waters and escape from aquaculture are the most important invasion vectors. During the last decade, an invasion of the round goby (Neogobius melanostomus) – a Ponto-Caspian fish species has been observed in the Gulf of Gdańsk. The first record of this fish in the Baltic Sea is from 1990. Early detection of the invader enabled the study of population growth and changes in the area. The first years of invasion were characterized by low numbers of individuals and a limited distribution. Later, the round goby gradually colonized all shallow waters in the western part of the Gulf of Gdańsk. Initially the fish inhabited stony and rocky habitats, but later it also occupied sandy bottoms. The round goby is now the dominating fish species in most of the shallow waters of the Gulf of Gdańsk. Two main factors account for the successful invasion of this fish in the region: the state of ecosystem at the time of the invasion and the biological features of N. melanostomus. In the late 1980s, the shallow waters of the Gulf of Gdańsk were almost devoid of piscivorous fishes. Concurrently, bivalves (a preferred prey of the round goby) have increased. Important is also parental care of laid eggs and reproductive strategy. Population growth potential enables the colonization of nearby regions. The first round gobies in the Vistula Lagoon were collected in 1999 and colonization of other Baltic Sea areas is anticipated.     

Is the invasion of Prorocentrum minimum (Dinophyceae) related to the nitrogen enrichment of the Baltic Sea?

The abundance of the invasive, bloom-forming dinoflagellate Prorocentrum minimum (Pavillard) Schiller and triangular, oval, and oval-round cell shapes were examined relative to salinity, temperature, and nutrient concentrations at the selected sites in the Baltic Sea. Based on the multiple regression and multivariate statistical analysis, all cell shapes of P. minimum had highly similar distribution relative to these environmental parameters as well as chlorophyll-a, nitrite + nitrate, ammonium, total nitrogen, phosphate, total phosphorus, and silicate. The species was related positively to total nitrogen, and negatively to salinity, temperature, nitrite + nitrate, and silicate:total nitrogen ratio. The results suggest that P. minimum could well adapt to low salinity and temperature and occurred particularly in coastal waters, rich in total nitrogen relative to silicate or other inorganic nutrients. These results indicate that the recent invasion of P. minimum into the Baltic Sea could have been enhanced by the DON enrichment. The results also support the suggestion that P. minimum is one morphospecies with no distinct subtaxa.     

The effect of salinity on the growth,toxin production,and morphology of <Emphasis Type="BoldItalic">Nodularia spumigena</Emphasis> isolated from the Gulf of Gdańsk,southern Baltic Sea

Culture experiments on the toxic Nodularia spumigena strain NSGG-1 isolated from the Gulf of Gdańsk showed a significant effect of salinity on growth and nodularin production. Growth of the NSGG-1 strain, was optimal between 7 and 18 psu, lower at 3 and 24 psu and was significantly inhibited at the extreme salinities of 0 and 35 psu. Nodularin (NOD) content of N. spumigena, estimated by the NOD/Chla ratios, correlated positively with salinity and increased from 0 to 35 psu. The NOD/Chla ratio on day 10 of growth was high, and, reached the maximum at day 30. A sudden increase in salinity from 7 to 18 and 35 psu resulted in plasmolysis of Nodularia cells. Salinity was also observed to have other effects on NSGG-1; the filaments were longest at 7 psu, while an increased number of akinetes were formed at 35 psu. The number of heterocytes was markedly reduced at the extreme salinities. This latter finding might explain why Nodularia blooms do not occur outside a certain salinity range in nitrogen-deficient waters.     

Population of <Emphasis Type="Italic">Aphanizomenon</Emphasis> from the Gulf of Gdańsk (Southern Baltic Sea): differences in phenotypic and genotypic characteristics

In this study, one of the major bloom-forming cyanobacteria in the Gulf of Gdańsk (Southern Baltic Sea), Aphanizomenon Morren ex Bornet et Flahaut has been characterized using a polyphasic approach by comparing phenotypic and molecular characteristics. The phenotypic analysis dealt with cell and filament morphology as well as ultrastructure. The molecular phylogenetic analyses were based on sequences of the 16S rRNA gene and the adjacent intergenic transcribed spacer (ITS). We have found the Aphanizomenon population from the Gulf of Gdańsk to be significantly different in ultrastructure, morphology from freshwater A. flos-aquae and according to the traditional approach; it could be assigned to different taxonomic units. However, genetic relationship with regard to sequences of the 16S rRNA gene, showed an high overall sequence identity (97.5–99%) to freshwater isolates. Similarly, ITS sequence identity among populations from the Baltic Sea and different freshwater isolates was as high as 90.3–97.7% suggesting one and the same species. Handling editor: D. Hamilton An erratum to this article can be found at     

Decreased Silica Land–sea Fluxes through Damming in the Baltic Sea Catchment – Significance of Particle Trapping and Hydrological Alterations

We tested the hypothesis that reservoirs with low water residence time and autochthonous production influence river biogeochemistry in eutrophied river systems draining cultivated watersheds. The effect of a single artificial water reservoir and consecutive reservoirs on silica (Si) river fluxes is exemplified by the moderately dammed Vistula River and the heavily regulated Daugava River that are compared with the practically undammed Oder River. The sum of the discharge weighted annual mean biogenic silica (BSi) and dissolved silicate (DSi) concentrations in the rivers Oder, Vistula and Daugava were about 160 μ M (40 + 120 μ M), 150 μ M (20 + 130 μ M) and 88 μ M (6 + 82 μ M), respectively. Assuming BSi and DSi concentrations as observed in the Oder River as typical for eutrophied but undammed rivers, complete trapping of this BSi could have lowered Si fluxes to the Baltic Sea from rivers with cultivated watersheds by 25%. The superimposed effect of hydrological alterations on reduced Si land–sea fluxes is demonstrated by studies in the boreal/subarctic and oligotrophic rivers Kalixälven and Lueälven. The DSi yield of the heavily dammed Luleälven (793 kg km^?2 yr^?1) constituted only 63% of that was found in the unregulated Kalixälven (1261 kg km^?2 yr^?1), despite the specific runoff of the Luleälven (672 mm m^?2 yr^?1) being 19% higher than that of theKalixälven (563 mm m^?2 yr^?1); runoff normalized DSi yield of the former, regulated watershed, was only half the DSi yield of the latter, unperturbed watershed. Based on these findings, it is hypothesized here that perturbed surface water–groundwater interactions are the major reasons for the reduced annual fluctuations in DSi concentrations as also seen in the heavily dammed and eutrophic river systems such as the Daugava and Danube.     

How does eutrophication affect different life stages of Fucus vesiculosus in the Baltic Sea? – a conceptual model

During the last few decades the perennial seaweed Fucus vesiculosus L. has rapidly declined in large parts of the Baltic Sea. Indirect effects of eutrophication, such as increased turbidity, sedimentation, grazing and occurrence of filamentous algae, have generally been suggested as major factors causing the decline. It is only recently, however, that the effects of these factors have been experimentally tested and here we summarise these results in a new conceptual model. In many areas, it might be desirable to enhance the recovery of Fucus artificially, as the natural rate of re-establishment of this important macroalga is limited both in time and space. To be able to optimise and evaluate the potential of restoring Fucus belts in eutrophicated areas, we need to know how eutrophication affects critical steps in its life cycle, such as the attachment, germination and early growth of germlings. We suggest that more attention should be given to the survival of early post-settlement stages in Fucusas they are crucial for the maintenance and re-establishment of populations. We also stress that the two reproductive periods that the species exhibits are included in discussions concerning effects of eutrophication on Fucus, as it is likely that the outcome of reproduction will differ between the two reproductive periods. In the new conceptual model we distinguish between the effects on adult and juvenile life stages and we add the two reproductive strategies of Fucus.     

Is it getting hot in here? Adjustment of hydraulic parameters in six boreal and temperate tree species after 5 years of warming

Global temperatures (T) are rising, and for many plant species, their physiological response to this change has not been well characterized. In particular, how hydraulic parameters may change has only been examined experimentally for a few species. To address this, we measured characteristics of the hydraulic architecture of six species growing in ambient T and ambient +3.4 °C T plots in two experimentally warmed forest sites in Minnesota. These sites are at the temperate–boreal ecotone, and we measured three species from each forest type. We hypothesized that relative to boreal species, temperate species near their northern range border would increase xylem conduit diameters when grown under elevated T. We also predicted a continuum of responses among wood types, with conduit diameter increases correlating with increases in the complexity of wood structure. Finally, we predicted that increases in conduit diameter and specific hydraulic conductivity would positively affect photosynthetic rates and growth. Our results generally supported our hypotheses, and conduit diameter increased under elevated T across all species, although this pattern was driven predominantly by three species. Two of these species were temperate angiosperms, but one was a boreal conifer, contrary to predictions. We observed positive relationships between the change in specific hydraulic conductivity and both photosynthetic rate (P = 0.080) and growth (P = 0.012). Our results indicate that species differ in their ability to adjust hydraulically to increases in T. Specifically, species with more complex xylem anatomy, particularly those individuals growing near the cooler edge of their range, appeared to be better able to increase conduit diameters and specific hydraulic conductivity, which permitted increases in photosynthesis and growth. Our data support results that indicate individual's ability to physiologically adjust is related to their location within their species range, and highlight that some wood types may adjust more easily than others.     

Recent developments in the biology of respiratory syncytial virus: are vaccines and new treatments just round the corner?

Respiratory syncytial virus (RSV) is the major cause of infantile bronchiolitis, and is an important pathogen in the elderly and in the developing world. The production of full length cDNA clones now allows precise genetic engineering of RSV, while knowledge of the immunopathogenesis of augmented disease gives hope that effective vaccines will soon be developed.     

Functional changes in the control of carbon fluxes after 3 years of increased drought in a Mediterranean evergreen forest?

Our objective was to test how a long‐term increased water limitation affects structural and functional properties of a Mediterranean ecosystem, and how these changes modify the response of the main carbon fluxes to climatic controls. In 2003, a 27% throughfall exclusion experiment was installed in a Quercus ilex L. forest in France. Gross primary production (GPP), ecosystem respiration (R_ECO) and net ecosystem exchange (NEE) were estimated in a control and a dry treatment. Decreasing throughfall decreased GPP by 14% and had a smaller effect on R_ECO (?12%), especially soil respiration R_S (?11%). Interannual variability of GPP (29%) was higher than for R_ECO (12%). Error propagation was used to estimates uncertainties in the NEE fluxes, which ranged from 3% to 10% in the control treatment but up to 167% for NEE in the dry treatment because more steps and data types were involved in the scaling. After 3 years of throughfall exclusion, we found no acclimation of R_S to climatic drivers. Functional properties of the response of R_S to soil water, temperature and rain pulse remained similar in the control and the dry treatments. A diurnal clockwise hysteresis in R_S was probably controlled by canopy photosynthesis with a 3 h lag. The proportion of diurnal variation of respiration due to photosynthesis was similar in all treatments (4–5%). Because of the characteristic of rain in Mediterranean climates, a continuous decrease of water input in these environments have an effect on topsoil water and consequently on R_S only during short periods when rainfall is characterized by infrequent and small events that does not allow the topsoil to reach field capacity and does not allow to dry completely. However, in the longer term, we expect a stronger decrease in R_S in the dry treatment driven by the decrease in GPP.     

Decentralisation of radiation therapy. Is it possible and beneficial to patients? Experience of the first 5 years of a satellite radiotherapy unit in the province of Tarragona,Spain

Background

The concept of satellite radiotherapy originates in countries whose populations are largely dispersed in order to treat homogenously the population by a unique fixed team.

Aim

This report describes the creation and management of a satellite radiotherapy unit in Spain (RUTE-Radiotherapy Unit, Terres de l’Ebre). It is managed by the Radiation Oncology Department at Hospital Universitari Sant Joan de Reus. We report the benefit gained in the comfort of patients and the economic benefit gained by reducing the expense of transport for the health care system.

Materials and methods

RUTE is equipped with a linear accelerator. A team of 10 physicians, specialised in different oncology pathologies, travel to RUTE on a rotational basis from the main Radiation Oncology Department. Simulation and planning of treatment is managed at the Radiation Oncology Department in Reus. Patients from RUTE only have to visit the centre in Reus once throughout the treatment process.

Results

Since August 2008, 1500 patients have completed treatment in the satellite unit. The implementation of RUTE has greatly improved the comfort of patients and along with that, there have been important savings in transport costs to the regional health care system.

Conclusions

Despite the high technological requirements of our speciality, decentralising radiotherapy is feasible. We can guarantee the highest standards of treatment with no differences from attending the main centre. It implies a clear benefit for the comfort of the patients and an economic benefit by decreasing transport costs.     

Invasive species are less parasitized than native competitors, but for how long? The case of the round goby in the Great Lakes-St. Lawrence Basin

There is increasing evidence that parasitism represents an unpredictable dimension of the ecological impacts of biological invasions. In addition to the risk of exotic pathogen transmission, other mechanisms such as parasite-release, could contribute to shaping the relationship between introduced species and native communities. In this study, we used the Eurasian round goby (Neogobius menalostomus) in the Great Lakes-St. Lawrence River ecosystem to further explore these ideas. As predicted by the parasite-release hypothesis, recently established populations of round goby were parasitized by a depauperate community of generalist helminths (8 taxa), all commonly found in the St. Lawrence River. In comparison, two native species, the logperch (Percina caprodes) and spottail shiner (Notropis hudsonius), were the hosts of 25 and 24 taxa respectively. Round gobies from each of 3 sampled localities were also less heavily infected than both indigenous species. This is in contrast to what is observed in round goby’s native range where the species is often the most parasitized among gobid competitors. This relative difference in parasite pressure could enhance its competitiveness in the introduced range. However, our study of an older population of round goby in Lake St. Clair suggests that this advantage over native species could be of short duration. Within 15 years, the parasite abundance and richness in the round goby has more than doubled whereas the number of parasite species per fish has increased to levels of those typical of fish indigenous to the St. Lawrence-Great Lakes watershed.     

Formation of hydroxyl radicals in the presence of ferritin and haemosiderin. Is haemosiderin formation a biological protective mechanism?

Horse spleen and human spleen ferritins increase the formation of hydroxyl radicals (OH) at both pH 4.5 and pH 7.4 in reaction mixtures containing ascorbic acid and H2O2. The generation of OH is inhibited by the chelator desferrioxamine. Human spleen haemosiderin also accelerates OH generation in identical reaction mixtures, but is far less effective (on a unit iron basis) than ferritin under all reaction conditions. It is proposed that conversion of ferritin into haemosiderin in iron overload is biologically advantageous in that it decreases the ability of iron to promote oxygen-radical reactions.     

Protein localization in E. coli: Is there a common step in the secretion of periplasmic and outer-membrane proteins?

An E. coli strain carrying a fusion of the malE and lacZ genes is induced for the synthesis of a hybrid protein, consisting of the N-terminal part of the maltose-binding protein and the enzymatically active C-terminal part of β-galactosidase, by addition of maltose to cells. The secretion of the protein is initiated by the signal peptide attached to the N terminus of the maltose-binding protein sequence, but is not completed, presumably because the β-galactosidase moiety of the hybrid protein interferes with the passage of the polypeptide through the cytoplasmic membrane. Thus the protein becomes stuck to the cytoplasmic membrane. Under such conditions, periplasmic proteins, including maltose-binding protein (encoded by the malE gene) and alkaline phosphatase, and the major outer-membrane proteins, including OmpF, OmpA and probably lipoprotein, are synthesized as precursor forms with unprocessed signal sequences. This effect is observed within 15 min after high levels of induction are achieved. The simplest explanation for these results and those of pulse-chase experiments is that specific sites in the cytoplasmic membrane become progressively occupied by the hybrid protein, resulting in an inhibition of normal localization and processing of periplasmic and outer-membrane proteins. These results suggest that most of the periplasmic and outer-membrane proteins share a common step in localization before the polypeptide becomes accessible to the processing enzyme. If this interpretation is correct, we can estimate that an E. coli cell has roughly 2 × 10⁴ such sites in the cytoplasmic membrane. A system is described for detecting the precursor of any exported protein.     

Ostreopsis cf. ovata in the Gulf of Gabès (south-eastern Mediterranean Sea): morphological,molecular and ecological characterization

In the last few decades, the frequency of the toxic benthic dinoflagellate Ostreopsis cf. ovata proliferation has increased in the Mediterranean Sea. These blooms are associated with harmful effects on human health and the environment. The present work provides the first long term study on the spatio-temporal distribution of O. cf. ovata in relation to physical parameters in the Gulf of Gabès coastal waters (south-eastern Mediterranean Sea), as well as its morphological, molecular and physiological features. The strains of O. cf. ovata were identified morphologically by light and epifluorescence microscopy. The morphology and the size range of cultured strains were similar to those described regarding O. cf. ovata isolated from the Mediterranean Sea. The ultrastructural analysis of O. cf. ovata cells using the transmission electron microscopy showed the presence of numerous vesicles (VE) containing spirally coiled fibers (SCFs) connected to the mucus canal (CH). The phylogenetic tree based on the internal transcribed spacer region containing the 5.8S rDNA (ITS-5.8S rDNA) revealed that O. cf. ovata strains were placed into the Mediterranean/Atlantic clade. In addition, O. cf. ovata toxicity was evaluated by the mouse bioassay and a dose level ≥ 4 × 10⁴ cells was found to be lethal to mice. The examination of the O. cf. ovata occurrence in the Gulf of Gabès at a large temporal scale (1997–2012) revealed a clear seasonal pattern with dominance from midsummer (July) to late autumn (November). Furthermore, a positive correlation was found between the abundance of O. cf. ovata and salinity, whereas no correlation was found as regards temperature. The occurrence of O. cf. ovata was only detected at salinity above 35 and the highest concentrations were observed at 45. Laboratory experiments confirmed such a result and showed that isolated O. cf. ovata strains had optimal growth at salinity ranging between 35 and 45, with its peak at 40.     

Is there chaos in the brain? I. Concepts of nonlinear dynamics and methods of investigation

In the light of results obtained during the last two decades in a number of laboratories, it appears that some of the tools of nonlinear dynamics, first developed and improved for the physical sciences and engineering, are well-suited for studies of biological phenomena. In particular it has become clear that the different regimes of activities undergone by nerve cells, neural assemblies and behavioural patterns, the linkage between them, and their modifications over time, cannot be fully understood in the context of even integrative physiology, without using these new techniques. This report, which is the first of two related papers, is aimed at introducing the non expert to the fundamental aspects of nonlinear dynamics, the most spectacular aspect of which is chaos theory. After a general history and definition of chaos the principles of analysis of time series in phase space and the general properties of chaotic trajectories will be described as will be the classical measures which allow a process to be classified as chaotic in ideal systems and models. We will then proceed to show how these methods need to be adapted for handling experimental time series; the dangers and pitfalls faced when dealing with non stationary and often noisy data will be stressed, and specific criteria for suspecting determinism in neuronal cells and/or assemblies will be described. We will finally address two fundamental questions, namely i) whether and how can one distinguish, deterministic patterns from stochastic ones, and, ii) what is the advantage of chaos over randomness: we will explain why and how the former can be controlled whereas, notoriously, the latter cannot be tamed. In the second paper of the series, results obtained at the level of single cells and their membrane conductances in real neuronal networks and in the study of higher brain functions, will be critically reviewed. It will be shown that the tools of nonlinear dynamics can be irreplaceable for revealing hidden mechanisms subserving, for example, neuronal synchronization and periodic oscillations. The benefits for the brain of adopting chaotic regimes with their wide range of potential behaviours and their aptitude to quickly react to changing conditions will also be considered.     

Can different vegetative states in shallow coastal bays of the Baltic Sea be linked to internal nutrient levels and external nutrient load?

Hydrobiologia - Two different vegetative states, i.e. one clear water state dominated by benthic macrophytes and one turbid state dominated by phytoplankton, are commonly found in shallow lakes. In...     

Inflammatory obstruction of the olfactory clefts and olfactory loss in humans: a new syndrome?

The first step in the olfactory perception is the activation by odorants of sensory neurones in the olfactory epithelium. In humans, this sensory epithelium is located at 2 narrow passages, the olfactory clefts, at the upper part of the nasal cavities. Little is known about the physiology of these clefts. We examined, in 34 patients, the impact of obstructed clefts upon detection and postlearning identification of 5 odorants. The location and extension of the obstructions were assessed using endoscopy, CT scans, and MRI. The inflammatory obstruction was usually bilateral, extending anteroposteriorly, and confined to the clefts, with no sign of obstruction or any inflammatory disease in the rest of the nasal cavities and sinuses. When tested with 5 odorants, these patients showed greatly impaired olfaction compared with a group of 73 normosmic subjects. The majority of these 34 patients had sensory deficits equivalent to that found in another group of 41 congenital anosmic patients, where inspection with MRI indicated the lack of olfactory bulbs. This study demonstrates that the olfactory clefts, in human, function as an entity that is different from other regions of the nasal cavity and is the target for local inflammatory events that are apparently not responding to corticoid and antibiotic treatments.