Ellipsomyxa gobii (Myxozoa: Ceratomyxidae) in the common goby Pomatoschistus microps (Teleostei: Gobiidae) uses Nereis spp. (Annelida: Polychaeta) as invertebrate hosts     

Køie M  Whipps CM  Kent ML 《Folia parasitologica》2004,51(1):14-18

Nereis diversicolor O.F. Müller and N. succinea Frey et Leuckart (Polychaeta, Nereidae) living in brackish shallow areas in Denmark are naturally infected with tetractinomyxon actinospores. Infected Nereis spp. were experimentally fed to various potential fish hosts, and the actinosporean stages developed into myxosporean stages of Ellipsomyxa gobii K?ie, 2003 (Ceratomyxidae) in the gallbladder of the common goby Pomatoschistus microps (Kr?yer) (Gobiidae). The European eel Anguilla anguilla (L.), three-spined stickleback Gasterosteus aculeatus L., small sand eel Ammodytes tobianus L., flounder Platichthys flesus (L.), European plaice Pleuronectes platessa L. and common sole Solea solea (L.) did not become experimentally infected. In Danish shallow brackish areas P. microps is naturally infected with E. gobii, in some areas with a prevalence >90%. We compared small subunit ribosomal DNA sequences of the actinosporean with E. gobii from P. microps. Sequences were identical, which further verifies that both forms belong to the same organism. This is the first myxozoan two-host life cycle in the marine environment.  相似文献   

Covariation in shape and foraging behaviour in lateral plate morphs in the three‐spined stickleback     

O. Bjærke  K. Østbye  H. M. Lampe  L. A. Vøllestad 《Ecology of Freshwater Fish》2010,19(2):249-256

Bjærke O, Østbye K, Lampe HM, Vøllestad LA. Covariation in shape and foraging behaviour in lateral plate morphs in the three‐spined stickleback. Ecology of Freshwater Fish 2010: 19: 249–256. © 2010 John Wiley & Sons A/S Abstract – In three‐spined stickleback (Gasterosteus aculeatus) colonisation of freshwater has led to rapid evolution in various morphological and behavioural traits. Examples are reduction in lateral plate number and increased benthic foraging. These changes are believed to result from natural selection, but the evolutionary mechanisms driving behavioural changes and how such changes are associated with phenotypes, are poorly understood. Here, we study three different lateral plate morphs from a brackish water lake and one morph from a river upstream. We investigate if the lateral plate morphs differ in overall body shape and then experimentally test how foraging behaviour differ among morphs and with body shape. Foraging behaviour is measured as the consumption efficiency of benthic and pelagic prey types. The results show that lateral plate morphs differ in overall body shape and that body shape significantly co‐varies with foraging behaviour.  相似文献   

Structural basis for gluten intolerance in celiac sprue   总被引：1，自引：0，他引：1  

Shan L  Molberg Ø  Parrot I  Hausch F  Filiz F  Gray GM  Sollid LM  Khosla C 《Science (New York, N.Y.)》2002,297(5590):2275-2279

Celiac Sprue, a widely prevalent autoimmune disease of the small intestine, is induced in genetically susceptible individuals by exposure to dietary gluten. A 33-mer peptide was identified that has several characteristics suggesting it is the primary initiator of the inflammatory response to gluten in Celiac Sprue patients. In vitro and in vivo studies in rats and humans demonstrated that it is stable toward breakdown by all gastric, pancreatic, and intestinal brush-border membrane proteases. The peptide reacted with tissue transglutaminase, the major autoantigen in Celiac Sprue, with substantially greater selectivity than known natural substrates of this extracellular enzyme. It was a potent inducer of gut-derived human T cell lines from 14 of 14 Celiac Sprue patients. Homologs of this peptide were found in all food grains that are toxic to Celiac Sprue patients but are absent from all nontoxic food grains. The peptide could be detoxified in in vitro and in vivo assays by exposure to a bacterial prolyl endopeptidase, suggesting a strategy for oral peptidase supplement therapy for Celiac Sprue.  相似文献   

Are polar bears threatened?     

Wiig Ø 《Science (New York, N.Y.)》2005,309(5742):1814-1815

  相似文献   

Field-saturated hydraulic conductivity of soils from laboratory constant-head well tests     

M.?RodgersEmail author  J.?Mulqueen 《Irrigation and Drainage Systems》2004,18(4):315-327

Field-saturated and unsaturated finite element analyses (FEA) of constant-head well percolation tests at three well pressure heads in two large tanks with three soils of widely differing field-saturated hydraulic conductivities (K_fs) were carried out. The results of these analyses were compared with those from the Glover classical approach. The A values in the Glover-type formula (A = K_fs/Q_s where A was a model parameter and Q_s was the FEA steady-state infiltration rate into the soil) were shown to be independent of soil type for a particular pressure head and soil condition. Constant-head well percolation tests were carried out in two laboratory sand tanks with the same dimensional arrangement used in the finite element analyses. Field saturation was maintained by spray irrigation, and in the unsaturated condition there was no spray irrigation. Following saturation and stabilisation of the well pressure heads, drainage ports were opened instantaneously and the rate of inflow into the well was recorded. The infiltration rates, Q_s, into the sand under the two soil conditions were multiplied by the appropriate A values from the FEA for each specific pressure head to derive K_fs. A values were significantly different under field-saturated and unsaturated conditions. K_fs of the sand was also measured independently in a constant-head permeameter. Values of K_fs from the FEA and the Glover approach were in close agreement with one another, and with that measured in the constant-head permeameter. Agreement was within 13% at the higher pressure heads. The procedure appears promising for field use.  相似文献   

The Chironomid (Diptera) Subfossil Record of Lille Hovvatn (Norway), with a Comparison with a Similar Study in Adjacent Store Hovvatn     

Øyvind Almskar Schnell 《Water, air, and soil pollution》2001,130(1-4):817-824

The subfossil chironomid community of Lille Hovvatn during the last 150 years was analysed. A short sediment core was taken in 1999, sliced at 0.5 cm intervals and dated using the ²¹⁰Pb method. A total of 1588 specimens were identified, most of them to species level, and 37 chironomid taxa were found. Effects of acidification were recorded on several species up-core, especially in the distribution of Micropsectra insignilobus and Stictochironomus rosenshoeldi. Ordination analysis showed that the chironomid community of Lille Hovvatn is different from the one in Store Hovvatn based on the abundance of the various species, but that the species composition is almost identical in the two lakes. The reappearance of S. rosenshoeldi in the upper 1 cm of the sediment in Lille Hovvatn probably is the first response among the chironomids to the increased pH values measured in the lake during the last decade.  相似文献   

Teratogenicity of elevated egg incubation temperature and egg vitamin A status in Atlantic salmon, Salmo salar L   总被引：1，自引：0，他引：1  

ØRnsrud R  Gil L  Waagbø R 《Journal of fish diseases》2004,27(4):213-223

The present study was undertaken to investigate the possibility that high egg vitamin A (VA) status in combination with elevated egg incubation temperatures may cause deformities in Atlantic salmon, Salmo salar L. Egg batches selected for their total VA concentration were exposed to low (normal, 8 degrees C) or elevated (14 degrees C) egg incubation temperatures. Temperature was the main factor causing bone deformities such as warped gill opercula, fin and jaw deformities, but not for the development of spinal deformities where all groups displayed a 'baseline' occurrence of mild deformity (decreased vertebral size in the cephalic region) and no systematic variation in the occurrence of serious spinal deformities (fused vertebrae). A possible effect of egg incubation temperature fluctuation was found for the groups reared at low temperatures. An indication of a negative effect of elevated egg VA status for the development of organ deformities such as missing septum transversum and situs inversus was found in addition to temperature effects, however, no firm conclusions could be drawn from the present data. The phenotypes for temperature-induced deformities resembled the phenotype of VA-induced deformities, but no clear conclusions on the causality of the deformities found in the present study could be drawn. Egg incubation temperatures, both absolute temperature and temperature variations, should therefore be strictly controlled.  相似文献   

Infection with atypical Aeromonas salmonicida in farmed common wolffish, Anarhichas lupus L.     

H Hellberg  E Moksness  S Høie 《Journal of fish diseases》1996,19(4):329-332

  相似文献   

Comparison of rotifer culture quality with yeast plus oil and algal-based cultivation diets     

G. øie  K. I. Reitan  Y. Olsen 《Aquaculture International》1994,2(4):225-238

The culture quality of rotifers, Brachionus plicatilis, was compared for yeast and algal-based cultivation diets. The rotifer quality was evaluated based on factors which may affect survival and growth of marine fish larvae, including individual length and biomass, nutritional value, bacterial content, and rotifer viability. The diets used were monocultures of Tetraselmis sp., Isochrysis galbana, Pavlova lutheri, and baker's yeast plus capelin oil.Rotifers grown to early stationary phase with equal food rations exhibited equal length distribution, but the rotifer individual biomass was 10–25% higher for yeast-grown rotifers than for algal-grown rotifers.All diets gave equal protein content of individual rotifers. The lipid content was slightly higher and the ratio of protein to lipid was slightly lower with yeast plus capelin oil than with algae. The fatty acid composition of the rotifers was closely related to that of their dietary lipids and the 3 fatty acid content was not systematically different for the two types of diets.Use of yeast plus capelin oil resulted in considerably higher numbers of both suspended and rotifer-associated bacteria than with use of algal diets. No differences were found for the algal species involved. The viability of the rotifers in a temperature and salinity test was far better in groups fed algae than in groups fed yeast plus capelin oil.The results indicated an overall better quality of rotifers cultivated with algae than for rotifers cultivated with yeast and oil. Questions related to proteins and the microflora of rotifers should be further emphasized in future research.  相似文献   

Influence of dietary fatty acids on the lipid composition of lipoproteins in farmed Atlantic salmon (Salmo salar)     

Øyvind Lie  Aslaug Sandvin  Rune Waagbø 《Fish physiology and biochemistry》1993,12(3):249-260

The dietary influence on the fatty acid composition of neutral lipids and phosphatidylcholine of very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL) of Atlantic salmon (Salmo salar) was studied, using soybean oil, capelin oil and sardine oil as lipid sources in the diets. The fish had a mean weight of 3 Kg and had been fed the experimental diets for 24 months. The results show that the fatty acid composition in the feed are important for the composition of the core lipids as well as the surface components of the lipoproteins.  相似文献