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31.
The annual routines and seasonal ecology of herbivorous zooplankton species are relatively well known due to their tight coupling with their pulsed food source, the primary production. For higher trophic levels of plankton, these seasonal interactions are less well understood. Here, we study the mid-winter feeding of chaetognaths in high-Arctic fjord ecosystems. Chaetognaths are planktivorous predators which comprise high biomass in high-latitude seas. We investigated the common species Parasagitta elegans around the Svalbard archipelago (78–81°N) during the winters of 2012 and 2013. Our samples consisted of individuals (body lengths 9–55 mm) from three fjords, which were examined for gut contents (n = 903), stable isotopes, fatty acid composition, and maturity status (n = 352). About a quarter of the individuals contained gut contents, mainly lipid droplets and chitinous debris, whilst only 4 % contained identifiable prey, chiefly the copepods Calanus spp. and Metridia longa. The δ15N content of P. elegans, and its average trophic level of 2.9, confirmed its carnivorous position and its fatty acid profile [in particular its high levels of 20:1(n-9) and 22:1(n-11)] confirmed carnivory on Calanus. Observations of undeveloped gonads in many of the larger P. elegans, and the absence of small individuals <10 mm, suggested that reproduction had not started this early in the year. Its average feeding rate across fjords and years was 0.12 prey ind.?1 day?1, which is low compared to estimates of spring and summer feeding in high-latitude environments. Our findings suggest reduced feeding activity during winter and that predation by P. elegans had little impact on the mortality of copepods. 相似文献
32.
Geir Steinheim Tormod Ådnøy Øyvind A. Voie Øystein Holand Kjetil S. Longva 《Small Ruminant Research》2011,100(1):30-33
The common military explosives 2-methyl-1,3,5-trinitrobenzene (TNT), 1,3,5-trinitroperhydro-1,3,5-triazine (RDX) and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) are distributed in many military training areas, and are thus encountered by grazing animals. The aim of this study was to examine small ruminant's intake of forage contaminated with explosives. An indoor, experimental setup was used to determine if contamination of forage by these compounds affected intake by sheep. The results clearly demonstrate that contamination by any of the three explosives reduced forage intake in sheep; in order of increasing avoidance: RDX < TNT < HMX. The results are discussed in a risk assessment context. 相似文献
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Vidar Selås Geir A. Sonerud Olav Hjeljord Lars Erik Gangsei Helge B. Pedersen Erik Framstad Tor Kristian Spidsø Øystein Wiig 《European Journal of Wildlife Research》2011,57(3):523-535
The plant stress hypothesis states that plant stress factors other than herbivory improve herbivore performance due to changes
in the content of nutritive or defensive compounds in the plants. In Norway, the bilberry (Vaccinium myrtillus) is important forage for the bank vole (Myodes glareolus) in winter and for the moose (Alces alces) in summer and autumn. The observed peaks in bank vole numbers after years with high production of bilberries are suggested
to be caused by increased winter survival of bank voles due to improved forage quality. High production of bilberries should
also lead to higher recruitment rates in moose in the following year. We predict, however, that there is an increasing tendency
for a 1-year delay of moose indices relative to vole indices with decreasing summer temperatures, because low temperatures
prolong the period needed by plants to recover in the vole peak year, and thus positively affect moose reproduction also in
the succeeding year. In eight out of nine counties in south-eastern Norway, there was a positive relationship between the
number of calves observed per female moose during hunting and a bilberry seed production index or an autumn bank vole population
index. When dividing the study area into regions, there was a negative relationship between a moose-vole time-lag index and
the mean summer temperature of the region. These patterns suggest that annual fluctuations in the production of bilberries
affect forage quality, but that the effect on moose reproduction also depends on summer temperatures. 相似文献
35.
In this study, we attempted to isolate novel mast cell-stimulating molecules from Staphylococcus aureus. Water-soluble extract of S. aureus cell lysate strongly induced human interleukin- 8 in human mast cell line-1 and mouse interleukin-6 in mouse bone marrow-derived mast cells. The active molecule was purified to homogeneity through a C(18) reverse phase HPLC column. By determination of its structure by MALDITOF and (1)H- and (13)C-NMR, adenosine was revealed to be responsible for the observed cytokine induction activities. Further studies using 8-sulfophenyl theophylline, a selective adenosine receptor blocker, verified that purified adenosine can induce interleukin-8 production via adenosine receptors on mast cells. Moreover, adenosine was purified from S. aureusengulfed RAW264.7 cells, a murine macrophage cell line, used to induce phagocytosis of S. aureus. These results show a novel view of the source of exogenous adenosine in vivo and provide a mechanistic link between inflammatory disease and bacterial infection. 相似文献
36.
Jørgensen KM Hjelle SM Øye OK Puntervoll P Reikvam H Skavland J Anderssen E Bruserud Ø Gjertsen BT 《Journal of Proteomics》2011,74(3):269-281
Protein and gene networks centred on the regulatory tumour suppressor proteins may be of crucial importance both in carcinogenesis and in the response to chemotherapy. Tumour suppressor protein p53 integrates intracellular data in stress responses, receiving signals and translating these into differential gene expression. Interpretation of the data integrated on p53 may therefore reveal the response to therapy in cancer. Proteomics offers more specific data - closer to "the real action" - than the hitherto more frequently used gene expression profiling. Integrated data analysis may reveal pathways disrupted at several regulatory levels. Ultimately, integrated data analysis may also contribute to finding key underlying cancer genes. We here proposes a Partial Least Squares Regression (PLSR)-based data integration strategy, which allows simultaneous analysis of proteomic data, gene expression data and classical clinical parameters. PLSR collapses multidimensional data into fewer relevant dimensions for data interpretation. PLSR can also aid identification of functionally important modules by also performing comparison to databases on known biological interactions. Further, PLSR allows meaningful visualization of complex datasets, aiding interpretation of the underlying biology. Extracting the true biological causal mechanisms from heterogeneous patient populations is the key to discovery of new therapeutic options in cancer. 相似文献
37.
Infectious pancreatic necrosis virus VP5 is dispensable for virulence and persistence 总被引:3,自引:0,他引:3
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Infectious pancreatic necrosis virus (IPNV) is the causative agent of infectious pancreatic necrosis (IPN) disease in salmonid fish. Recent studies have revealed variation in virulence between isolates of the Sp serotype, associated with certain residues of the structural protein VP2. The isolates are also highly heterogenic in the coding region of the nonstructural VP5 protein. To study the involvement of this protein in the pathogenesis of disease, we generated three recombinant VP5 mutant viruses using reverse genetics. The "wild-type" recombinant NVI15 (rNVI15) virus is virulent, having a premature stop codon at nucleotide position 427, putatively encoding a truncated 12-kDa VP5 protein, whereas rNVI15-15K virus encodes a 15-kDa protein. Recombinant rNVI15-deltaVP5 virus contains a mutation in the initiation codon of the VP5 gene that ablates the expression of VP5. Atlantic salmon postsmolts were challenged to study the virulence characteristics of the recovered viruses in vivo. The role of VP5 in persistent infection was investigated by challenging Atlantic salmon fry with the recovered viruses, as well as with the low-virulence field strain Sp103 and a naturally occurring VP5-deficient mutant of Sp103. The results show that VP5 is not required for viral replication in vivo, and its absence does not alter the virulence characteristics of the virus or the establishment of persistent IPNV infection. 相似文献
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39.
Boar taint is mainly caused by two components; skatole (3-methylindole) and androstenone. By castrating the male pigs, boar taint will be avoided. In Norway, castration of pigs will no longer be permitted after 2009. This represents a substantial cost for the Norwegian swine production. Other Norwegian studies have shown that a large proportion of pigs are above the consumer detection limits for these two chemical components. The obvious question for the geneticist arises: Is it possible to select against skatole and androstenone in a breeding programme? Skatole is produced in the gut by bacteria. It is then absorbed in the blood stream. Skatole is either metabolised in the liver or transported and stored in fatty tissue. Androstenone is produced in the testis, and its biochemical pathway is related to the pathway of testosterone. In this study, fatty tissue was collected from the carcasses of Norwegian Landrace and Duroc boars, and analysed for androstenone and skatole. The length of glandula bulbourethralis was measured on the same animals, as this is regarded as a good indicator of sexual maturation. Heritabilities of androstenone and skatole were substantial. The two components were genetically correlated. Sexual maturation was also highly heritable. However, correlations to both androstenone and skatole were significantly unfavourable. 相似文献
40.
Merete Thune Wiiger Hege B. Gehrken Øystein Fodstad Gunhild M. Mælandsmo Yvonne Andersson 《Cancer immunology, immunotherapy : CII》2010,59(11):1665-1674
Screening a phage-display single-chain antibody library for binding to the breast cancer cell line PM-1 an antibody, scFv173,
recognising activated leukocyte cell adhesion molecule (ALCAM, CD166) was isolated and its binding profile was characterized.
Positive ALCAM immunohistochemical staining of frozen human tumour sections was observed. No ALCAM staining was observed in
the majority of tested normal human tissues (nine of ten). Flow cytometry analyses revealed binding to 22 of 26 cancer cell
lines of various origins and no binding to normal blood and bone marrow cells. Antibody binding inhibited invasion of the
breast cancer cell line MDA-MB-231 by 50% in an in vitro Matrigel-coated membrane invasion assay. Reduced growth of tumours
in nude mice was observed in an in vivo model in which the mice were injected subcutaneously with colorectal carcinoma HCT
116 cells and treated with scFv173 when compared to control. In summary, we have characterized a novel fully human scFv antibody
recognising ALCAM on cancer cells and in tumour tissues that reduces cancer cell invasion and tumour growth in accordance
with the hypothesised role for ALCAM in cell growth and migration control. 相似文献