Discovery of the toxic dinoflagellate Pfiesteria in northern European waters.

Several dinoflagellate strains of the genus Pfiesteria were isolated by culturing techniques from sediment samples taken in the Oslofjord region of Norway. Pfiesteria piscicida, well known as a fish killer from the Atlantic coast of America, was identified by genetic methods and light microscopy. The related species Pfiesteria shumwayae was attracted from the sediment by the presence of fish, and has proved toxic. This present survey demonstrates the wide distribution of these potentially harmful species, but so far they have not been connected with fish kills in Europe.     

Nuclear corrosion monitoring—

Nuclear corrosion technique has been developed for the assay of various heavy metals released through corrosion and abrasion into electrolytes from various biomaterials like amalgams, chromium— cobalt and gold alloys, steel, and titanium. Application of the technique in measurement of selective release rates under static or dynamic conditions, i.e., during cyclic loading, is discussed. The elements chromium, cobalt, copper, gold, iron, mercury, molybdenum, silver, titanium, and zinc have been quantitatively assessed. In vivo corrosion measurements are further included. By combining the present nuclear tracer technique with ESCA technique, knowledge about reaction mechanisms occurring at the interface solid/liquid is obtained. Exposure of humans to various heavy metals from biomaterials, e.g., dental materials, can be estimated using the NCM technique. The technique also has a potential for selective release measurements of several nuclides possessing suitable radioanalytical properties from other types of alloys immersed in various liquid environments.     

Robot-Mediated Interviews - How Effective Is a Humanoid Robot as a Tool for Interviewing Young Children?

Robots have been used in a variety of education, therapy or entertainment contexts. This paper introduces the novel application of using humanoid robots for robot-mediated interviews. An experimental study examines how children’s responses towards the humanoid robot KASPAR in an interview context differ in comparison to their interaction with a human in a similar setting. Twenty-one children aged between 7 and 9 took part in this study. Each child participated in two interviews, one with an adult and one with a humanoid robot. Measures include the behavioural coding of the children’s behaviour during the interviews and questionnaire data. The questions in these interviews focused on a special event that had recently taken place in the school. The results reveal that the children interacted with KASPAR very similar to how they interacted with a human interviewer. The quantitative behaviour analysis reveal that the most notable difference between the interviews with KASPAR and the human were the duration of the interviews, the eye gaze directed towards the different interviewers, and the response time of the interviewers. These results are discussed in light of future work towards developing KASPAR as an ‘interviewer’ for young children in application areas where a robot may have advantages over a human interviewer, e.g. in police, social services, or healthcare applications.     

Correction to: In vitro cellular and proteome assays identify Wnt pathway and CDKN2A-regulated senescence affected in mesenchymal stem cells from mice after a chronic LD gamma irradiation in utero

Radiation and Environmental Biophysics -     

Locomotor Activity Patterns in Ilybius fenestratus (Fabricius) (Coleoptera,Dytiscidae) in a Central Norwegian Lake,with Evidence for Breeding-Induced Arrhythmicity

The diel activity of Ilybius fenestratus was studied in Målsj?en, a lake in S?r-Tr?ndelag, Central Norway (63°14'N, 10°26'E), during 1971–1972. Adults and larvae were sampled in activity traps every week during March–October and every 2–3 weeks during November–February. The traps were emptied every 2 hrs during a 24- hr period. The diel locomotor activity of I. fenestratus was clearly nocturnal, except in the second half of July, for the males also in the first half of July, when surprisingly the population showed an arrhythmic activity pattern. The arrhythmicity is connected with the mating and egg-laying period of the species. The larvae were also nocturnal in the autumn, but showed arrhythmicity under the ice during the winter.     

Drivers of vegetative dormancy across herbaceous perennial plant species

Vegetative dormancy, that is the temporary absence of aboveground growth for ≥ 1 year, is paradoxical, because plants cannot photosynthesise or flower during dormant periods. We test ecological and evolutionary hypotheses for its widespread persistence. We show that dormancy has evolved numerous times. Most species displaying dormancy exhibit life‐history costs of sprouting, and of dormancy. Short‐lived and mycoheterotrophic species have higher proportions of dormant plants than long‐lived species and species with other nutritional modes. Foliage loss is associated with higher future dormancy levels, suggesting that carbon limitation promotes dormancy. Maximum dormancy duration is shorter under higher precipitation and at higher latitudes, the latter suggesting an important role for competition or herbivory. Study length affects estimates of some demographic parameters. Our results identify life historical and environmental drivers of dormancy. We also highlight the evolutionary importance of the little understood costs of sprouting and growth, latitudinal stress gradients and mixed nutritional modes.     

Global change‐driven effects on dissolved organic matter composition: Implications for food webs of northern lakes

Northern ecosystems are experiencing some of the most dramatic impacts of global change on Earth. Rising temperatures, hydrological intensification, changes in atmospheric acid deposition and associated acidification recovery, and changes in vegetative cover are resulting in fundamental changes in terrestrial–aquatic biogeochemical linkages. The effects of global change are readily observed in alterations in the supply of dissolved organic matter (DOM)—the messenger between terrestrial and lake ecosystems—with potentially profound effects on the structure and function of lakes. Northern terrestrial ecosystems contain substantial stores of organic matter and filter or funnel DOM, affecting the timing and magnitude of DOM delivery to surface waters. This terrestrial DOM is processed in streams, rivers, and lakes, ultimately shifting its composition, stoichiometry, and bioavailability. Here, we explore the potential consequences of these global change‐driven effects for lake food webs at northern latitudes. Notably, we provide evidence that increased allochthonous DOM supply to lakes is overwhelming increased autochthonous DOM supply that potentially results from earlier ice‐out and a longer growing season. Furthermore, we assess the potential implications of this shift for the nutritional quality of autotrophs in terms of their stoichiometry, fatty acid composition, toxin production, and methylmercury concentration, and therefore, contaminant transfer through the food web. We conclude that global change in northern regions leads not only to reduced primary productivity but also to nutritionally poorer lake food webs, with discernible consequences for the trophic web to fish and humans.     

Heterologous Production of Antimicrobial Peptides in Propionibacterium freudenreichii

Heterologous bacteriocin production in Propionibacterium freudenreichii is described. We developed an efficient system for DNA shuttling between Escherichia coli and P. freudenreichii using vector pAMT1. It is based on the P. freudenreichii rolling-circle replicating plasmid pLME108 and carries the cml(A)/cmx(A) chloramphenicol resistance marker. Introduction of the propionicin T1 structural gene (pctA) into pAMT1 under the control of the constitutive promoter (P₄) yielded bacteriocin in amounts equal to those of the wild-type producer Propionibacterium thoenii 419. The P. freudenreichii clone showed propionicin T1 activity in coculture, killing 90% of sensitive bacteria within 48 h. The pamA gene from P. thoenii 419 encoding the protease-activated antimicrobial peptide (PAMP) was cloned and expressed in P. freudenreichii, resulting in secretion of the pro-PAMP protein. Like in the wild type, PAMP activation was dependent on externally added protease. Secretion of the antimicrobial peptide was obtained from a clone in which the pamA signal peptide and PAMP were fused in frame. The promoter region of pamA was identified by fusion of putative promoter fragments to the coding sequence of the pctA gene. The P₄ and P_pamp promoters directed constitutive gene expression, and activity of both promoters was enhanced by elements upstream of the promoter core region.     

Immunofluorescence studies on the effect of cyclic adenosine 3′,5′-monophosphate in tissue culture preparations of the cervicovaginal anlage from neonatal mice

Summary The authors have studied the production of antigenic material, specific for the cervicovaginal epithelium, in organ cultures of the cervicovaginal region from neonatal mice. In control cultures the antigenic material appeared at a time corresponding to the normal appearance under in vivo conditions. When cyclic adenosine 3, 5-monophosphate (dibutyryl derivate) was added to the medium, a strong increase of the fluorescent material was seen.This investigations was supported by grants from the Norwegian Research Council and the Norwegian Cancer Society (Landsforeningen mot Kreft).     

Effects of Naringenin on Oxidative Stress and Histopathological Changes in the Liver of Lead Acetate Administered Rats

Lead has several adverse effects on the body due to one of the environmental pollutants. We aimed to determine the effects of naringenin on the oxidative stress and the hepatic damage against lead acetate treatment in the liver of male rats. Naringenin was administered by orogastric gavage (50 mg/kg) and lead acetate was given as daily 500 parts per million in drinking water for 4 weeks. Lead and antioxidant activities were measured, and histopathological evaluation was performed in the liver. Lead concentrations, malondialdehyde, and antioxidant activity were restored by the naringenin. The grade of necrosis, hydropic degeneration, and hepatic cord disorganization was decreased by the naringenin. However, there were no differences in the degree of sinusoidal congestion, hepatic steatosis, and capsular fibrosis between lead acetate and naringenin + lead acetate groups. We can suggest that naringenin has antioxidant and chelating effects in the liver. Nevertheless, this effect is not enough against the lead acetate induced hepatic injury.