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  • 1
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During early development in fish, phospholipase A2 (EC 3.1.1.4) regulates membrane lipid modifications, which relates to changes in environmental conditions and provision of fatty acids required for metabolic energy substrates and prostaglandin biosynthesis. A method to analyze phospholipase A2 in rat tissues has been modified to measure its activity in embryonic Atlantic halibut (Hippoglossus hippoglossus L.). Egg and embryo samples were collected during the 1994 spawning season. Enzyme activity was undetectable at fertilization but in 10-d embryos was 230 pmol mg−1 h−1 (at 20 °C) and increased by ∼120% at hatch (17-d). Significant alterations in the fatty acid composition of important phospholipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE), were also observed. The content of some critical polyunsaturated fatty acids, and the ratio of unsaturated/saturated fatty acids, declined significantly over development. Acyl-chain restructuring mediated through the activity of phospholipase A2, coupled with other observed lipid changes (significant increases in the PC/PE ratio and cholesterol content), would produce a decreased fluidity of membranes during embryonic development, coinciding with the predicted upward movement of larvae in the water column. Arachidonic acid (20:4n-6) removed from PE could serve as a precursor for biosynthesis of 2-series prostaglandins, and eicosapentaenoic acid (20:5n-3) from PC is a likely source for other prostaglandin types. Despite removal of polyunsaturated fatty acids, there was an overall increase in lipid and fatty acid concentration, which can be attributed to amino acid catabolism during early developmental stages.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, U.K. and Cambridge, USA : Blackwell Science Ltd
    Histopathology 33 (1998), S. 0 
    ISSN: 1365-2559
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: To evaluate the pattern of cadherin expression in epithelioid sarcoma.〈section xml:id="abs1-2"〉〈title type="main"〉Methods and resultsSeven epithelioid sarcomas were immunostained by a polyclonal antibody that detects all cadherin subtypes and by monoclonal antibodies that detect epithelial cadherin (E-cadherin) and vascular-endothelial cadherin (VE cadherin). In addition, the tumours were immunostained for a variety of epithelial (cytokeratin, EMA, AUA1) and endothelial (Factor VIII-related antigen, CD34, CD31) markers. Tumour cells of all seven epithelioid sarcomas expressed cadherins. Surprisingly, E-cadherin was not detected in any of the sarcomas. VE-cadherin was detected in five of seven cases. All seven tumours expressed cytokeratins and EMA but none expressed AUA1. CD34 was detected in six of seven cases and CD31 was detected in a single case. No case expressed Factor VIII-related antigen.〈section xml:id="abs1-3"〉〈title type="main"〉ConclusionsMost epithelioid sarcomas strongly express cadherins, a feature which may contribute to their epithelioid appearance. The absence of detectable E-cadherin suggests that epithelial differentiation in these tumours is, at most, incomplete. The expression of VE-cadherin by the majority of cases, in the absence of E-cadherin, is consistent with an element of mesenchymal differentiation, possibly endothelial or perineurial. The additional presence of other markers such as CD34 and CD31 in some cases favours endothelial differentiation.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, U.K. and Cambridge, USA : Blackwell Science Ltd
    Plant pathology 47 (1998), S. 0 
    ISSN: 1365-3059
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Movement of barley powdery mildew (caused by Erysiphe graminis f.sp. hordei) within fields was investigated by sowing the barley cultivars Tyra and Jupiter side by side in two field plots, and trapping spores along transects within the plots. The trapped spores were tested for virulence on the two cultivars. The epidemic on Tyra developed quickly, and a gradient in the proportion of spores with virulence on Tyra was detected in the Jupiter half-plots. In the Jupiter half-plots, the epidemic was much less severe; and no mildew could be found in one plot. Movement of spores from one half of the plot to the other usually declined steeply in the first 4 m from the boundary, and was not detectable beyond 12 m. There were exceptions where the gradient was much shallower, and these were consistent with differences in wind direction.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: NMDA receptors mediate several important functions in the CNS; however, little is known about the pharmacology, biochemistry, and function of distinct NMDA receptor subtypes in brain tissue. To facilitate the study of native NMDA receptor subpopulations, we have determined the radioligand binding properties of [3H]homoquinolinate, a potential subtype-selective ligand. Using quantitative receptor autoradiography, NMDA-specific [3H]homoquinolinate binding selectively labeled brain regions expressing NR2B mRNA (layers I–III of cerebral cortex, striatum, hippocampus, and septum). NMDA-specific [3H]homoquinolinate binding was low in brain regions that express NR2C and NR2D mRNA (cerebellar granular cell layer, NR2C; glomerular layer of olfactory bulb, NR2C/NR2D; and midline thalamic nuclei, NR2D). In forebrain, the pattern of NMDA-specific [3H]homoquinolinate binding paralleled NR2B and not NR2A distribution. In addition to NMDA-displaceable binding, there was a subpopulation of [3H]homoquinolinate binding sites in the forebrain, cerebellum, and choroid plexus that was not displaced by NMDA or l-glutamate. In contrast, we found that the derivative of homoquinolinate, 2-carboxy-3-carboxymethylquinoline, markedly inhibited the NMDA-insensitive binding of [3H]homoquinolinate without inhibiting the NMDA-sensitive population. [3H]Homoquinolinate may be useful for selectively characterizing NR2B-containing NMDA receptors in a preparation containing multiple receptor subtypes and for characterizing a novel binding site of unknown function.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Plant Physiology and Plant Molecular Biology 49 (1998), S. 77-95 
    ISSN: 1040-2519
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Biology
    Notes: Abstract The purpose of this review is to highlight the unique and common features of splice site selection in plants compared with the better understood yeast and vertebrate systems. A key question in plant splicing is the role of AU sequences and how and at what stage they are involved in spliceosome assembly. Clearly, intronic U- or AU-rich and exonic GC- and AG-rich elements can influence splice site selection and splicing efficiency and are likely to bind proteins. It is becoming clear that splicing of a particular intron depends on a fine balance in the "strength" of the multiple intron signals involved in splice site selection. Individual introns contain varying strengths of signals and what is critical to splicing of one intron may be of less importance to the splicing of another. Thus, small changes to signals may severely disrupt splicing or have little or no effect depending on the overall sequence context of a specific intron/exon organization.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford : Blackwell Science Ltd
    Anaesthesia 53 (1998), S. 0 
    ISSN: 1365-2044
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The pain from insertion of two small cannulae was compared in 26 volunteers. Each subject was blindfolded and had both a 22G and a 20G cannula inserted in random order. One subject was rejected as cannulation was unsuccessful. Of the remaining 25 subjects, 12 found the 22G more painful and 13 the 20G. This difference was not significant (chi squared p 〉 0.1).
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Pharmaceutical research 15 (1998), S. 1026-1030 
    ISSN: 1573-904X
    Keywords: hard gelatin capsule ; cross-linking ; disintegration ; scintigraphy ; gastrointestinal tract
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. To evaluate if the cross-linking of gelatin affects in vivo capsule disintegration. Methods. Scintigraphic investigation in nine healthy volunteers to provide for a real time visualisation of capsule disintegration. Results. The moderately stressed capsules failed the USP dissolution specification for acetaminophen capsule when tested in water and conventional SGF but passed with the addition of pepsin. Moderately stressed capsules started to disintegrate at 10 ± 6 minutes (range 6 to 24 minutes) compared to 8 ± 2 minutes (range 5 to 11 minutes) for the unstressed capsule. Conclusions. The results of the study clearly demonstrate that with the incisive technique of gamma scintigraphy there are no differences in the in vivodisintegration properties of moderately stressed and unstressed capsules.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 259 (1998), S. 327-335 
    ISSN: 1617-4623
    Keywords: Key words Insertional mutagenesis ; Aspergillus fumigatus ; Electroporation ; Restriction enzyme-mediated integration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We have investigated transformation with heterologous DNA as a method for insertional mutagenesis of Aspergillus fumigatus. Two methods, polyethylene glycol-mediated transformation of protoplasts and electroporation of germinating spores, were used to establish conditions leading to single-copy integration of transforming DNA at different genomic sites. We have assessed the effect of restriction enzyme-mediated integration (REMI) for both methods. Non-REMI protoplast transformation led to integration of multiple copies of transforming DNA in the majority of transformants. Results of REMI with protoplast transformation varied depending on the enzyme used. Low concentrations of several restriction enzymes stimulated transformation, but of ten enzymes investigated only REMI with XhoI and KpnI resulted in single-copy integration of transforming DNA for the majority of transformants. For protoplast transformation with XhoI- or KpnI-based REMI, 50% and 76% of insertions, respectively, were due to integrations at a genomic enzyme site corresponding to the enzyme used for REMI. Electroporation of spores without addition of restriction enzyme resulted in a high transformation efficiency, with up to 67% of transformants containing a single copy of transforming DNA. In contrast to protoplast transformation, electroporation of spores in the presence of a restriction enzyme did not improve transformation efficiency or lead to insertion at genomic restriction sites. Southern analysis indicated that for both protoplast transformation with REMI using KpnI or XhoI and for electroporation of spores without addition of restriction enzymes, transforming DNA inserted at different genomic sites in a high proportion of transformants.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1617-4623
    Keywords: Key words Two-component system ; Osmotic adaptation ; HOG pathway ; Histidine kinase ; Response regulator
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Activation and control of the yeast HOG (High Osmolarity Glycerol) MAP kinase cascade is accomplished, in part, by a two-component sensory-response circuit comprised of the osmosensing histidine protein kinase Sln1p, the phospho-relay protein Ypd1p, and the response regulator protein Ssk1p. We found that deletion of SLN1 and/or YPD1 reduces reporter gene transcription driven by a second two-component response regulator – Skn7p. The effect of sln1Δ and ypd1Δ mutations upon Skn7p activity is dependent on a functional two-component phosphorylation site (D427) in Skn7p, suggesting that Sln1p and Ypd1p may act as phosphodonors for Skn7p. We also observed that loss of PTC1 (a protein serine/threonine phosphatase implicated in negative control of the HOG pathway) in a skn7Δ background results in severely retarded growth and in morphological defects. Deletion of either PBS2 or HOG1 alleviates the slow growth phenotype of ptc1Δskn7Δ cells, suggesting that Skn7p may participate, in concert with known regulatory components, in modulating HOG pathway activity. The contribution of Skn7p to HOG pathway regulation appears to be modulated by the receiver domain, since non-phosphorylatable Skn7pD427N is unable to fully restore growth to ptc1/skn7 cells.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Archives of virology 143 (1998), S. 731-742 
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary.  Rt-PCR probes targeted to different gene sequences of VEE (Venezuelan equine encephalitis) virus strain TC-83 were assessed for their sensitivity, specificity and non-specific cross-reactivity. A generic VEE virus amplimer (VNSP4F2/VNSP4R2), targeted against nsP4 was identified, which was sensitive (detected at least 10 pfu) and robust (worked over a wide range of salt concentrations and annealing temperatures). An E2 amplimer designed against TC-83, (VE2F/VE2R), identified VEE strains TRD (1AB), P676 (1C), 3880 (1D) Everglades (2) vRNA whilst a second E2 primer pair designed against strain 68U201, (68UF/68UR), identified all the remaining VEE viruses in the sero-complex. This would suggest that the VEE virus E2 gene can be sub-divided at the genetic level into two separate groups making it a useful target for differentiation of sero-subtypes 1 and 2 from the other VEE virus subtypes. Using a panel of amplimers targeted to different VEE genes and strains it was possible to distinguish between most of the serotypes, but most importantly, we were able to detect the epizootic strains TRD and P676 as well as other VEE viruses implicated in human disease (sero-subtypes 1D and 1E).
    Type of Medium: Electronic Resource
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