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  • 1
    ISSN: 1432-1939
    Keywords: Forest decline ; Carbohydrates ; Picea abies ; Growth ; Leaf area index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary This is the first in a series of papers on the growth, photosynthetic rate, water and nutrient relations, root distribution and mycorrhizal frequency of two Norway spruce forests at different stages of decline. One of the stands was composed of green trees only while the other included trees ranging in appearance from full green crowns to thin crowns with yellow needles. In this paper we compare the growth and carbohydrate relations of the two stands and examine relationships among growth variables in ten plots. The declining stand produced 65 percent of the wood per ground area compared with the stand in which all trees were green because its foliage produced less wood at any level of leaf area index. The difference in foliage efficiency between the sites could not be explained by differeneces in climate, competition or stand structure. The declining stand appeared to have lower carbon gain as indicated by a smaller increase in reserve carbohydrates before bud break, and weaker sinks for carbohydrates as indicated by less use of the stored carbohydrates than the healthy stand. Thus, growth reduction was probably related to factors which affect both photosynthesis and, even more, the sinks for carbohydrate.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-1939
    Keywords: Picea abies ; Forest decline ; Xylem flow ; Whole tree transpiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The water relations of Picea abies in a healthy stand with green trees only and a declining stand with trees showing different stages of needle yellowing were investigated in northern Bavaria. The present study is based on observations of trees differing in their nutritional status but apparently green on both sites in order to identify changes in the response pattern which might be caused by atmospheric concentrations of air pollutants and could lead to the phenomenon of decline. Transpiration was measured as water flow through the hydroactive xylem using an equilibrium mass-flow measurement system. Total tree transpiration was monitored diurnally, from July 1985 until October 1985 at both sites. The relationship between transpiration and meteorological measurements indicated that transpiration was a linear function of the vapor pressure deficit. No differences in transpiration of green trees were observed between the two sites. Canopy transpiration was 57%–68% of total throughfall and 41%–54% of total rainfall. Due to this positive water balance, soil water potential at 10 and 20 cm depths remained close to-0.02 MPa (max.-0.09 MPa) for most of the summer. Soil water potential was correlated with the difference between the weekly precipitation and transpiration. No differences in the water relations of apparently healthy trees in the two P. abies stands were observed. It is concluded that differences between green trees at the two sites in terms of nutrient relations or growth rate cannot be explained by changes in whole-tree transpiration or soil water status.
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  • 3
    ISSN: 1432-1939
    Keywords: Forest decline ; Ectomycorrhizas ; Fine roots ; Picea abies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The development of root tips and apparent ectomycorrhizas was compared in the Fichtelgebirge (FRG) over one growing season in two 30-year-old Picea abies stands, both on soils derived from phyllite but showing varying symptoms of decline. Visual symptoms of tree decline reflected a lower relative and absolute mycorrhizal frequency, a lower number of ectomycorrhizas per m2 leaf area and an uneven vertical distribution of root tips and ectomycorrhizas. The number of apparent ectomycorrhizas per ground area was correlated with the amount of magnesium, calcium, and ammonium, and the pH in the free-drainage soil solution, and with the molar calcium to aluminium ratio in mineral soil extracts. The foliage concentrations of magnesium and calcium were correlated with the numbers of apparent ectomycorrhizas per m2 leaf or ground area. These observations were used to formulate testable hypotheses concerning the role of the root system and the soil environment in forest decline.
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  • 4
    Publication Date: 1989-09-08
    Description: Complementary DNAs for the beta subunit of the dihydropyridine-sensitive calcium channel of rabbit skeletal muscle were isolated on the basis of peptide sequences derived from the purified protein. The deduced primary structure is without homology to other known protein sequences and is consistent with the beta subunit being a peripheral membrane protein associated with the cytoplasmic aspect of the sarcolemma. The protein contains sites that might be expected to be preferentially phosphorylated by protein kinase C and guanosine 3',5'-monophosphate-dependent protein kinase. A messenger RNA for this protein appears to be expressed in brain.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ruth, P -- Rohrkasten, A -- Biel, M -- Bosse, E -- Regulla, S -- Meyer, H E -- Flockerzi, V -- Hofmann, F -- New York, N.Y. -- Science. 1989 Sep 8;245(4922):1115-8.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Institut fur Physiologische Chemie, Medizinische Fakultat, Homburg/Saar, Federal Republic of Germany.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2549640" target="_blank"〉PubMed〈/a〉
    Keywords: Amino Acid Sequence ; Animals ; Calcium Channel Blockers/*metabolism/pharmacology ; Calcium Channels/drug effects/*metabolism ; Dihydropyridines/*metabolism/pharmacology ; Molecular Sequence Data ; Muscles/*analysis ; Phosphorylation ; Protein Conformation ; RNA, Messenger/isolation & purification ; Rabbits ; Receptors, Nicotinic/drug effects/*isolation & purification/metabolism
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 5
    Publication Date: 1989-06-16
    Description: Antibodies that enhance human immunodeficiency virus (HIV) infectivity have been found in the blood of infected individuals and in infected or immunized animals. These findings raise serious concern for the development of a safe vaccine against acquired immunodeficiency syndrome. To address the in vivo relevance and mechanism of this phenomenon, antibody-dependent enhancement of HIV infectivity in peripheral blood macrophages, lymphocytes, and human fibroblastoid cells was studied. Neither Leu3a, a monoclonal antibody directed against the CD4 receptor, nor soluble recombinant CD4 even at high concentrations prevented this enhancement. The addition of monoclonal antibody to the Fc receptor III (anti-FcRIII), but not of antibodies that react with FcRI or FcRII, inhibited HIV type 1 and HIV type 2 enhancement in peripheral blood macrophages. Although enhancement of HIV infection in CD4+ lymphocytes could not be blocked by anti-FcRIII, it was inhibited by the addition of human immunoglobulin G aggregates. The results indicate that the FcRIII receptor on human macrophages and possibly another Fc receptor on human CD4+ lymphocytes mediate antibody-dependent enhancement of HIV infectivity and that this phenomenon proceeds through a mechanism independent of the CD4 protein.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Homsy, J -- Meyer, M -- Tateno, M -- Clarkson, S -- Levy, J A -- AI-26471/AI/NIAID NIH HHS/ -- R01-AI-24499/AI/NIAID NIH HHS/ -- New York, N.Y. -- Science. 1989 Jun 16;244(4910):1357-60.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Medicine, School of Medicine, University of California, San Francisco 94143.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2786647" target="_blank"〉PubMed〈/a〉
    Keywords: Acquired Immunodeficiency Syndrome/*immunology ; Animals ; Antibodies, Monoclonal ; Antibody-Dependent Cell Cytotoxicity ; Guinea Pigs ; HIV Antibodies/biosynthesis/*immunology ; HIV-1/*immunology ; HIV-2/*immunology ; Humans ; In Vitro Techniques ; Pan troglodytes ; Receptors, Fc/*physiology ; Receptors, HIV ; Receptors, Virus/*physiology
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 6
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    American Association for the Advancement of Science (AAAS)
    Publication Date: 1988-04-29
    Description: The kinetics of calcium release by inositol 1,4,5-trisphosphate (IP3) in permeabilized rat basophilic leukemia cells were studied to obtain insight into the molecular mechanism of action of this intracellular messenger of the phosphoinositide cascade. Calcium release from intracellular storage sites was monitored with fura-2, a fluorescent indicator. The dependence of the rate of calcium release on the concentration of added IP3 in the 4 to 40 nM range showed that channel opening requires the binding of at least three molecules of IP3. Channel opening occurred in the absence of added adenosine triphosphate, indicating that IP3 acts directly on the channel or on a protein that gates it. The channels were opened by IP3 in less than 4 seconds. The highly cooperative opening of calcium channels by nanomolar concentrations of IP3 enables cells to detect and amplify very small changes in the concentration of this messenger in response to hormonal, sensory, and growth control stimuli.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Meyer, T -- Holowka, D -- Stryer, L -- AI22449/AI/NIAID NIH HHS/ -- GM24032/GM/NIGMS NIH HHS/ -- GM30387/GM/NIGMS NIH HHS/ -- New York, N.Y. -- Science. 1988 Apr 29;240(4852):653-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Cell Biology, Sherman Fairchild Center, Stanford University School of Medicine, CA 94305.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2452482" target="_blank"〉PubMed〈/a〉
    Keywords: Animals ; Basophils ; Benzofurans ; Calcimycin/pharmacology ; Calcium/*metabolism ; Cell Membrane Permeability ; Cytoplasm/metabolism ; Fluorescent Dyes ; Fura-2 ; Inositol 1,4,5-Trisphosphate ; Inositol Phosphates/metabolism/*pharmacology ; Ion Channels/drug effects/*metabolism ; Kinetics ; Leukemia, Experimental/metabolism ; Rats ; Spectrometry, Fluorescence ; Sugar Phosphates/*pharmacology ; Tumor Cells, Cultured
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 7
    Publication Date: 1987-11-13
    Description: The long-term effects of excitotoxic lesions in the nucleus basalis magnocellularis of the rat were found to mimic several neuropathological and chemical changes associated with Alzheimer's disease. Neuritic plaque-like structures, neurofibrillary changes, and neuronal atrophy or loss were observed in the frontoparietal cortex, hippocampus, amygdala, and entorhinal cortex 14 months after the lesions were made. Cholinergic markers in neocortex were reduced, while catecholamine and indoleamine metabolism was largely unaffected at this time. Bilateral lesions of the nucleus basalis magnocellularis increased somatostatin and neuropeptide Y in the cortex of the rat by at least 138 and 284 percent, respectively, suggesting a functional interaction between cholinergic and peptidergic neurons that may differ from that in Alzheimer's disease.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Arendash, G W -- Millard, W J -- Dunn, A J -- Meyer, E M -- HD 17933/HD/NICHD NIH HHS/ -- New York, N.Y. -- Science. 1987 Nov 13;238(4829):952-6.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Department of Biology, University of South Florida, Tampa 33620.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2890210" target="_blank"〉PubMed〈/a〉
    Keywords: Acetylcholinesterase/metabolism ; Animals ; Biogenic Amines/metabolism ; Brain/metabolism/*pathology ; Cerebral Cortex/metabolism/*pathology ; Choline/metabolism ; Choline O-Acetyltransferase/metabolism ; Male ; Neuropeptide Y/analysis ; Olivary Nucleus/*physiology ; Organ Specificity ; Rats ; Rats, Inbred Strains ; Somatostatin/analysis
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 8
    Publication Date: 1985-01-11
    Description: Bidirectional coupling of action potential activity occurs between unmyelinated fibers in the normal peripheral nerve of monkey. The site of coupling is near the cutaneous nociceptive receptor associated with one of the fibers. This coupling could be due to an electrical synapse and could provide the basis for the flare associated with the axon reflex.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Meyer, R A -- Raja, S N -- Campbell, J N -- NS-00519/NS/NINDS NIH HHS/ -- NS-14447/NS/NINDS NIH HHS/ -- New York, N.Y. -- Science. 1985 Jan 11;227(4683):184-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/3966152" target="_blank"〉PubMed〈/a〉
    Keywords: Action Potentials ; Animals ; Electric Stimulation ; Macaca fascicularis ; Nerve Fibers/physiology ; Peripheral Nerves/*physiology ; Sensory Receptor Cells/physiology ; Skin/injuries
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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  • 9
    Publication Date: 1985-11-29
    Description: Hepatocyte-stimulating factor and interleukin-1 are proteins produced by monocytes in response to inflammatory challenge. Neither of these monokines had direct effects on steroid production by cultured adrenocortical cells. Both monokines stimulated pituitary cells (AtT-20) to release adrenocorticotropic hormone; interleukin-1 was equipotent with a combination of corticotropin-releasing factor and arginine vasopressin, and hepatocyte-stimulating factor was at least three times as effective. The synthetic glucocorticoid, dexamethasone, inhibited production of hepatocyte-stimulating factor by cultured monocytes. These results indicate an axis between monocytes and pituitary and adrenocortical cells which may play a role in regulating host defense.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Woloski, B M -- Smith, E M -- Meyer, W J 3rd -- Fuller, G M -- Blalock, J E -- AI 18932/AI/NIAID NIH HHS/ -- IR01AM338-39-01A1/AM/NIADDK NIH HHS/ -- R01-H120201/PHS HHS/ -- New York, N.Y. -- Science. 1985 Nov 29;230(4729):1035-7.〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/2997929" target="_blank"〉PubMed〈/a〉
    Keywords: Adrenal Glands/metabolism ; Adrenocorticotropic Hormone/*secretion ; Animals ; Interleukin-1/pharmacology ; Interleukin-6 ; Mice ; Monocytes/*physiology ; Monokines ; Pituitary-Adrenal System/*physiology ; Proteins/*pharmacology ; Secretory Rate/drug effects
    Print ISSN: 0036-8075
    Electronic ISSN: 1095-9203
    Topics: Biology , Chemistry and Pharmacology , Computer Science , Medicine , Natural Sciences in General , Physics
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