Air pollution as a possible cause for the decline of some phanerogamic species in The Netherlands

In The Netherlands the decline of some phanerogamic species cannot be readily explained from obvious factors such as lowering of the groundwater table, eutrophication or land reclamation. For a number of species the hypothesis was tested that the decline is partly due to air pollution. A two-factor model was made in which decline is accounted for by (a) habitat destruction assessed from topographic maps and (b) air pollution measured as the SO₂ 95-percentile over the winter period 1978/1979. Effects of both factors were assumed to follow a sigmoid dose-effect curve. For a number of species decline proved to be significantly correlated with air pollution. These are notably species from the syntaxon Violion caninae. A comparison was made with results obtained for epiphytic lichens. It appears that for some phanerogamic species sensitivity is about the same as for moderately sensitive lichens.Nomenclature follows Heukels & van der Meijden (1983).Thanks are due to the Rijksherbarium, for providing some of their unpublished data; and to Ada Groeneveld, for technical assistance.     

Localization of calcium in skeletal and cardiac muscle

Summary The requirement of calcium (Ca²⁺) in the excitation-contraction coupling of both skeletal and cardiac muscle is well established. However, the exact location of the intracellular storage sites of Ca²⁺ is not firmly established. We report here on the ultrastructural distribution of Ca²⁺ in white and red skeletal muscle and in cardiac muscle of the rat using combined phosphate-pyroantimonate (PPA) and oxalate-pyroantimonate (OPA) procedures. The methods are based on (a) stabilization and/or trapping of Ca²⁺ during the primary fixation step in glutaraldehyde by potassium phosphate or oxalate; (b) subsequent wash-out of all non-trapped cations such as Na⁺ and Mg²⁺ in potassium phosphate or oxalate; (c) conversion of the complexed or trapped Ca²⁺ into an electron-dense calcium pyroantimonate salt in 100 m-thick tissue sections; and (d) wash-out of the excess potassium pyroantimonate at alkaline pH.With the OPA procedure, mitochondria of all muscle types showed little precipitate. The junctional sarcoplasmic reticulum was stongly reactive in relaxed white skeletal muscle, negative in contracted white fibres and negative in red skeletal and cardiac muscle, independent of the state of relaxation-contraction. Other organelles were essentially free of deposits.With the PPA method, the precipitate was almost exclusively confined to the sarcolemma and its T-tubular invaginations in cardiac and slow skeletal muscle, and was absent in fast skeletal muscle. Apart from occasional deposits in mitochondria, all other organelles were free of precipitate. The sarcolemma-associated deposits were clearly confined to the inner leaflet of the lipid bilayer. The amount of precipitate varied within the contraction cycle, relaxed cells possessing the highest density.Exposure of the tissue to La³⁺ resulted in the complete absence of sarcolemma-bound precipitate suggesting that the Ca²⁺ is exchangeable. Furthermore, these cytological data suggest a basic difference in Ca²⁺ storage between white skeletal muscle on the one hand, and red skeletal and cardiac muscle on the other.     

Catecholamine im Hypothalamus vom Goldfisch (Carassius auratus)

Zusammenfassung Mit der fluoreszenzmikroskopischen Methode zur Lokalisation von Catechol- und Tryptaminen wurden im Hypothalamus von Carassius auratus zwei bisher unbekannte catecholaminhaltige Kerngebiete gefunden. Sie liegen in der Pars posterior des Lobus medius hypothalami und werden Nucleus recessus posterioris und Nucleus recessus lateralis genannt. Aus diesen Kerngebieten gehen vier markarme Bahnen hervor, die ungekreuzt verlaufen und innerhalb des Hypothalamus endigen. Verschiedene pharmakologische und histochemische Befunde legen die Vermutung nahe, daß die fluoreszierende Substanz im Hypothalamus Noradrenalin ist. Eine Abgabe von biogenen Aminen in den Liquor cerebrospinalis wird für möglich gehalten.

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Summary The hypothalamus of Carassius auratus was investigated by means of the method for fluorescence-microscopical detection of catechol- and tryptamines. The hypothalamus was found to contain two hitherto unknown nuclei with specific catecholamine-fluorescence. They are situated in the pars posterior of the lobus medius hypothalami and are termed nucleus recesaus lateralis and nucleus recessus posterions. The unmyelinated axons of these nuclei give rise to four different tracts which run uncrossed in the frontal direction and terminate within the hypothalamus. Their course is described in detail. According to the results of histochemical and pharmacological tests it is assumed that the fluorescent substance in the hypothalamus is noradrenaline. The two nuclei are bordering the ventricular wall and are thought to secrete catecholamines into the cerebrospinal fluid.

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Mit dankenswerter Unterstützung durch eine Sachbeihilfe der Joachim-Jungius-Gesellschaft zur Förderung der Wissenschaften, Hamburg.     

Localization of GABA-like immunoreactivity in the ectostriatum of domestic chicks: GABA immunocytochemistry combined with Golgi impregnation

Brain Cell Biology - The distribution of GABA-like immunoreactivity (GABA-LI) in the ectostriatal core (Ec) of domestic chicks (one to two days old) was investigated using (1) preembedding GABA...     

Distribution of myosin and the glial fibrillary acidic protein (GFA Protein) in rat spinal cord and in the human frontal cortex as revealed by immunofluorescence microscopy

Summary The glial fibrillary acidic (GFA) protein and myosin were localized in rat spinal cord and human frontal cortex using specific antibodies against GFA protein from human spinal cord and highly purified smooth myosin from chicken gizzard by means of an indirect immunofluorescence microscopical approach. A strong GFA protein and myosin immunoreactivity was found in astrocytes of the white and grey matter and in the external glial limitans membrane. The very fine branches of astrocytic processes stained with antiGFA protein, but not with anti-myosin. Similar results were obtained with the human frontal cortex, where myosin antibodies failed to reveal the very fine branches of protoplasmic astrocytes.As a whole, staining with the GFA protein antiserum was more crisp than with the myosin antibody.Thanks are due to Professor J.R. Wolff, Max-Planck Institute for Biophysical Chemistry, Göttingen, for stimulating discussions, to Ursula König, Christa Mahlmeister and Renate Steffens for skilful technical assistance, and to Heidi Waluk for the photographic workSupported by grants from Deutsche Forschungsgemeinschaft (Br 634/1, Dr 91/1, Un 34/4, Ste 105/19)Dedicated to Prof. Dr. med. H. Leonhardt on the occasion of his 60. birthday     

Transparent Golgi Impregnations: A Way to Examine Both Details of Cellular Processes and Components of the Nerve Cell Body

A method is described by which the precipitate that normally fills impregnated cells in Golgi preparations is confined to a thin and transparent scattering of fine particles that defines the somata and cellular processes. The coating is stable enough to withstand counterstaining and thus makes possible direct evaluation of structural features not only of cellular processes but also of cytoplasmic components.     

The impact of acidification on diatoms and chemistry of Dutch moorland pools

Summary Moorland pools are shallow oligotrophic soft water lakes on poorly buffered sandy soils. Diatom assemblages of samples from 16 pools taken in 1920 and 1978 were compared by analysis of pH-spectra, diversity, dissimilarity and multivariate statistical techniques.The pH-spectra of pools in the southern (S) and central (C) part of the country indicate a fall in pH from 4.5–6.0 in the old samples to 3.7–4.6 in the recent ones. The pH-spectra of the northern pools (N) do not indicate a significant shift from the original pH (ca 4.5).The number of species in the count and the diversity (indices of Simpson and Shannon) decreased significantly in S+C, and that goes also for the dissimilarity index of Dyer. No changes were found in N.The first component (PC 1) of the principal component analysis explains 61% of total variance. PC 1 is correlated with log [SO₄] (r=0.83, p<0.001) and even better (r=0.95, p<0.001) with the relative sulphate concentration,i.e. the ratio of sulphate to all major anions (sulphate, chloride, bicarbonate). All old samples have low scores on PC 1, recent samples have low scores on the second (PC 2) and third (PC 3) principal component. Old samples have high scores on PC 2 and PC 3, explaining 9 and 6% of total variance, respectively.The orginal variation, caused by regional factors, is replaced by a SO₄ ^2– controlled variation. PC 1 is nearly completely determined by the relative abundance ofEunotia exigua. This species, which is known to be very resistant to pollution by sulphur, aluminium and heavy metals, increased largely from 1920 to 1978.In spite of the rather homogeneous distribution of wet sulphate deposition in the Netherlands, substantial differences in SO₄ ^2– content in the pools are observed, being lowest in N (0.13–0.48 meq.l^–1) and highest in S+C (0.38–1.65 meq.l^–1). Sulphate is positively correlated with calcium, aluminum and magnesium but negatively with factors that characterize humic acid waters (e.g. permanganate-consumption, iron and the ratio of univalent to divalent cations). Sulphate concentration depends on the intensity of sulphate reduction, accumulation by dry deposition in surrounding forests of Scots pine, drought and atmospheric deposition.     

Pigment architecture of the human telencephalic cortex

Summary Cortical lamination and parcellation of the retrosplenial region in the human brain is evaluated with the aid of frontal serial sections stained for nerve cells (15 m), myelin sheaths (100 m), and lipofuscin granules (800 m).For the most part, the retrosplenial region is buried in the depth of the sulcus corporis callosi covering the posterior parts of the cingulate gyrus. It lies between the supracallosal derivatives of the allocortex (fascia dentata, cornu ammonis, subiculum) and the mature parietal isocortex.The region can be subdivided into five areas. The transitory periallocortical Area ectosplenialis is followed by a richly differentiated proisocortical core displaying extremely externopyramidal, externoteniate, and astriate to unitostriate characteristics. The parvocellular core is averagely poor in pigment (Typus clarus) and rich in myelinated fibres (Typus dives). Minor structural differences allow for its subdivision into a lateral, an intermediate, and a medial retrosplenial field. The accompanying Area parasplenialis is adjacent to the equoteniate parietal isocortex. It is only weakly externopyramidal, externoteniate, and propebistriate. The already homotypical field shows an average pigmentation and myelin content. These structural features permit its classification as a belt area of the retrosplenial core.Supported by grants from the Deutsche Forschungsgemeinschaft     

Compositional turnover and variation in Eemian pollen sequences in Europe

Vegetation History and Archaeobotany - The Eemian interglacial represents a natural experiment on how past vegetation with negligible human impact responded to amplified temperature changes...     

Sensitivity to weighting in life cycle impact assessment (LCIA)

The International Journal of Life Cycle Assessment - Weighting in life cycle assessment (LCA) incorporates stakeholder preferences in the decision-making process of comparative LCAs. Research...