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  • Immunocytochemistry  (6)
  • pH  (5)
  • Springer  (11)
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  • Springer  (11)
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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of bioenergetics and biomembranes 20 (1988), S. 571-584 
    ISSN: 1573-6881
    Keywords: (Na+ + K+)-ATPase ; 3-O-methylfluorescein phosphate ; nitrophenyl phosphate ; dimenthyl sulfoxide ; Pi ; pH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract With 3-O-methylfluorescein phosphate (3-OMFP) as substrate for the phosphatase reaction catalyzed by the (Na+ + K+)-ATPase, a number of properties of that reaction differ from those with the common substratep-nitrophenyl phosphate (NPP): theK m is 2 orders of magnitude less and the Vmax is two times greater, and dimethyl sulfoxide (Me2SO) inhibits rather than stimulates. In addition, reducing the incubation pH decreases both theK m and Vmax for K+-activated 3-OMFP hydrolysis as well as theK 0.5 for K+ activation. However, reducing the incubation pH increases inhibition by Pi and the Vmax for 3-OMFP hydrolysis in the absence of K+. When choline chloride is varied reciprocally with NaCl to maintain the ionic strength constant, NaCl inhibits K+-activated 3-OMFP hydrolysis modestly with 10 mM KCl, but stimulates (in the range 5–30 mM NaCl) with suboptimal (0.35 mM) KCl. In the absence of K+, however, NaCl stimulates increasingly over the range 5–100 mM when the ionic strength is held constant. These observations are interpreted in terms of (a) differential effects of the ligands on enzyme conformations; (b) alternative reaction pathways in the absence of Na+, with a faster, phosphorylating pathway more readily available to 3-OMFP than to NPP; and (c) a (Na+ + K+)-phosphatase pathway, most apparent at suboptimal K+ concentrations, that is also more readily available to 3-OMFP.
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of paleolimnology 12 (1994), S. 103-154 
    ISSN: 1573-0417
    Keywords: acidification ; alkalization ; pH ; alkalinity ; diatoms ; sediment chemistry ; New England ; catchment effects ; land use ; logging ; acidic deposition ; air pollutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Studies of sediment cores from 12 acidic lakes in granitic, forested and uninhabited catchments in northern New England, U.S.A. produced diatom-inferred pH (IpH) 5.2 to 5.8 and alkalinity (Ialk) −12 to 31 µeq l−1, with slowly declining values at some lakes, for one to four centuries prior to logging. Increases of IpH (Δ0.05 to 0.60) and Ialk (Δ5 to 40 µeq l−1) correlate with logging in the catchments in the early-1800s to early-1900s. Recovery to pre-logging IpH and Ialk correlates with forest succession toward conifers, and is completed in the late-1800s to mid-1900s. Beginning at 1915–1920 (4 lakes), 1930–1950 (4 lakes) and 1965–1970 (4 lakes), IpH and Ialk start decreasing below pre-logging values due to atmospheric acidic deposition, leading to respective total decreases of 0.10 to 0.45 (X=0.25) and 5 to 25 µeq l−1 (X=15). Inputs of anthropogenic Pb, Zn, V, polycyclic aromatic hydrocarbons, and soot from the atmosphere are first detectable in early- to late-1800s sediment, and Cu in late-1800s sediment, increase rapidly in the late-1800s to mid-1900s, and level off or decrease since the 1960s — partly due to emission controls. Decreasing Ca, Mn, and possibly Zn relative to other metals and normalized to organic content, and increasing flux of Fe to the lakes, indicate soil and water acidification after 1900.
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Plant and soil 126 (1990), S. 237-246 
    ISSN: 1573-5036
    Keywords: Al3+ ; Ca2+ ; Mg2+ ; NH4 + ; NO3 − ; SO4 2− ; Al toxicity ; forest dieback ; Fagus sylvatica ; Nothofagus ; pH ; Picea abies ; soil solution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Concentrations of ions were measured in soil solutions from beech (Nothofagus) forests in remote areas of New Zealand and in solutions from beech (Fagus sylvatica) and Norway spruce (Picea abies) forests in North-East Bavaria, West Germany, to compare the chemistry of soil solutions which are unaffected by acid deposition (New Zealand) with those that are affected (West Germany). In New Zealand, soil solution SO4 2− concentrations ranged between 〈2 and 58 μmol L−1, and NO3 − concentrations ranged between 〈1 and 3 μmol L−1. In West Germany, SO4 2− concentrations ranged between 80 and 700 μmol L−1, and NO3 − concentrations at three of six sites ranged between 39 and 3750 μmol L−1, but was not detected at the remaining three sites. At all sites in New Zealand, and at sites where the soil base status was moderately high in West Germany, pH levels increased, and total Al (Alt) and inorganic monomeric Al (Ali) levels decreased rapidly with increasing soil depth. In contrast, at sites on soils of low base status in West Germany, pH levels increased only slightly, and Al levels did not decline with increasing soil depth. Under a high-elevation Norway spruce stand showing severe Mg deficiency and dieback symptoms in West Germany, soil solution Mg2+ levels ranged between 20 and 60 μmol L−, and were only half those under a healthy stand. Alt and Ali levels were substantially higher the healthy stand than under the unhealthy stand, indicating that Al toxicity was not the main cause of spruce decline.
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  • 4
    ISSN: 1573-5117
    Keywords: pH ; alkalinity ; indicators
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A series of laboratory and field studies were conducted to evaluate the reliability of colorimetric pH indicators in dilute, acidic surface waters in New England. Laboratory studies consisted of comparing colorimetric and electrometric pH results in synthetic solutions with a range of ionic strength and buffering capacity. Field studies involved simultaneous colorimetric and electrometric pH determinations in 52 New England lakes with differing water chemistry. Colorimetric indicators deviated from electrometric pH results at low alkalinities and near the end of their operating range. They agreed with electrometric values, within 0.2 unit, at alkalinities of 20 µeq 1-1 and greater, or near the center of their operating range. Changing ionic strength without changing buffering capacity did not affect results. When indicators were selected that bracketed sample pH, colorimetric determinations of pH in New England lakes agreed well with electrometric determinations.
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  • 5
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Photoreceptor cells ; Rhodopsin ; Membrane recycling ; Cherax destructor (Crustacea)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Examination of the ultrastructure of retinula cells of the Australian crayfish Cherax destructor at different times over a 24-hour cycle, together with patterns of anti-rhodopsin antigenicity, has lead to the formulation of a model of photoreceptor membrane turnover in these animals. Its main features are: (a) the existence of two bursts of rhabdomeral membrane breakdown; one, light-sensitive and synchronous, occurring at dawn, the other, constituting the first part of the membrane replacement phase itself, occurring during the afternoon and night, (b) the desynchronisation of the replacement phase of turnover between animals and to a lesser extent between cells of the same retina, (c) confinement of ultrastructurally detectable signs of photoreceptor membrane processing to the retinula cells themselves, and (d) replacement of a substantial part if not all of the rhabdomeral membrane daily. This model is compatible with many of the observations reported on the American crayfish Procambarus, and utilises the same basic mechanisms that are believed to operate in photoreceptor membrane turnover in many other arthropod compound eyes.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Hydrobiologia 120 (1985), S. 69-87 
    ISSN: 1573-5117
    Keywords: diatoms ; lake acidification ; acidic precipitation ; paleolimnology ; pH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The pH history of lakes can be inferred from diatom remains in dated sediment cores. To derive transfer functions for pH inference in acidic lakes, we counted diatoms in surface-sediment from 31 soft-water lakes in n. New England (NE) and 36 in Norway (N), covering pH 4.4–7.1. Cluster analysis of each data set indicates that pH 6 is an upper limit for a group of similar diatom assemblages. For each set, we developed multiple linear regressions to relate three versions of the diatom data to pH of surface-waters: (1) relative frequencies of selected diatom taxa, (2) the first principal component (1 PC) of these frequencies, and (3) the frequencies of Hustedt pH groups. Also, simple linear regressions were developed for two versions: (1) Index B and (2) Index Alpha, both based on pH groups. Regressions were run separately for lakes with pH ≤ 6; these are most relevant for pH inference in acidic lakes. The best regressions (N: taxa & 1 PC taxa) have r2 0.69–0.91 and Se 0.24–0.31 pH units, the worst (NE: log alpha) have r2 0.27–0.57 and Se 0.51. In all cases, errors for NE are greater than N, partly due to greater diversity of NE lakes. Regressions based on pH groups (directly & by indices) have smaller r2 and larger Se than those based on taxa and 1 taxa. The Index Alpha is least useful because its requirement for alkaline diatom units is unsatisfied at many acidic lakes. Regressions based on taxa may give erratic pH inferences due to sensitivity to unusual frequencies of individual taxa; this effect is reduced by using 1 PC taxa. Four regressions based on pH ≤ 6 lakes were used for inferring pH in a 210Pb dated core from Nedre Målmesvatn, N (now pH 4.6). There is good agreement among three of the four (not for the regression based directly on taxa) that there has been a decrease of ca. 0.6 pH units starting in the late 1800's.
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 276 (1994), S. 69-83 
    ISSN: 1432-0878
    Keywords: Immunocytochemistry ; Vasopressin ; Diuresis ; Neurohemal organ ; Evolution ; Nauphoeta cinerea ; Aedes aegypti ; Acheta domesticus ; Schistocerca americana (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Antisera were raised against leucokinin IV, a member of the leucokinin peptide family. Immunohistochemical localization of leucokinin immunoreactivity in the brain of the cockroach Nauphoeta cinerea revealed neurosecretory cells in the pars intercerebralis and pars lateralis, several bilateral pairs of interneurons in the protocerebrum, and a group of interneurons in the optic lobe. Several immunoreactive interneurons were found in the thoracic ganglia, while the abdominal ganglia contained prominent immunoreactive neurosecretory cells, which projected to the lateral cardiac nerve. The presence of leucokinins in the abdominal nerve cord was confirmed by HPLC combined with ELISA. Leucokinin-immunoreactive neurosecretory cells were also found in the pars intercerebralis of the cricket Acheta domesticus and the mosquito Aedes aegypti, but not in the locust Schistocerca americana or the honey bee Apis mellifera. However, all these species have leucokinin-immunoreactive neurosecretory cells in the abdominal ganglia. The neurohemal organs innervated by abdominal leucokinin-immunoreactive cells were different in each species.
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  • 8
    ISSN: 1432-0878
    Keywords: Neuropeptides ; Diuresis, insects ; Neurosecretory cells ; Immunocytochemistry ; Manduca sexta (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Because leucokinins stimulate diuresis in some insects, we wished to identify the neurosecretory cells in Manduca sexta that might be a source of leucokinin-like neurohormones. Immunostaining was done at various stages of development, using an antiserum to leucokinin IV. Bilateral pairs of neurosecretory cells in abdominal ganglia 3–7 of larvae and adults are immunoreactive; these cells project via the ipsilateral ventral nerves to the neurohemal transverse nerves. The immunoreactivity and size of these lateral cells greatly increases in the pharate adult, and this change appears to be related to a period of intensive diuresis occurring a few days before adult eclosion. Relationships of these neurons to cells that are immunoreactive to a M. sexta diuretic hormone were also investigated. Diuretic hormone and leucokinin immunoreactivity are co-localized in the lateral neurosecretory cells and their neurohemal projections. A median pair of leucokinin-immunoreactive, and a lateral pair of diuretic hormone-immunoreactive neurons in the larval terminal abdominal ganglion project to neurohemal release sites within the cryptonephridium. The immunoreactivity of these cells is lost as the cryptonephridium is eliminated during metamorphosis. This loss appears to be related to the change from the larval to adult pattern of diuresis.
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  • 9
    ISSN: 1432-0878
    Keywords: Key words: Neuropeptides ; Diuresis ; insects ; Neurosecretory cells ; Immunocytochemistry ; Manduca sexta (Insecta)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Because leucokinins stimulate diuresis in some insects, we wished to identify the neurosecretory cells in Manduca sexta that might be a source of leucokinin-like neurohormones. Immunostaining was done at various stages of development, using an antiserum to leucokinin IV. Bilateral pairs of neurosecretory cells in abdominal ganglia 3–7 of larvae and adults are immunoreactive; these cells project via the ipsilateral ventral nerves to the neurohemal transverse nerves. The immunoreactivity and size of these lateral cells greatly increases in the pharate adult, and this change appears to be related to a period of intensive diuresis occurring a few days before adult eclosion. Relationships of these neurons to cells that are immunoreactive to a M. sexta diuretic hormone were also investigated. Diuretic hormone and leucokinin immunoreactivity are co-localized in the lateral neurosecretory cells and their neurohemal projections. A median pair of leucokinin-immunoreactive, and a lateral pair of diuretic hormone-immunoreactive neurons in the larval terminal abdominal ganglion project to neurohemal release sites within the cryptonephridium. The immunoreactivity of these cells is lost as the cryptonephridium is eliminated during metamorphosis. This loss appears to be related to the change from the larval to adult pattern of diuresis.
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 240 (1985), S. 593-600 
    ISSN: 1432-0878
    Keywords: Serotonin ; Immunocytochemistry ; Visceral nerves ; Neurohemal system ; Periplaneta americana
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By use of the indirect immunofluorescent technique applied to whole mounts of tissues and organs of the American cockroach, Periplaneta americana, serotonin-like reactivity has been demonstrated in an extensive meshwork of fibers on the surface of nerves of the subesophageal ganglion and the tritocerebrum. This meshwork appears to serve the neurohemal release of serotonin. In addition, several of these nerves contain two or more centrally located axons that appear to be serotonergic. The corpora cardica show immunoreactivity but do not appear to be a principal release site for serotonin. The nerves and ganglia of the stomadeal nervous system show immunoreactivity for serotonin and provide serotonin-positive innervation to the salivary glands and the visceral muscles of the stomodeum and midgut. The heart, hindgut, Malpighian tubules, fat body, and skeletal muscles all appear to lack serotonin immunoreactivity.
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