Pinus roxburghii stand dynamics at a heavily impacted site in Nepal: Research through an educational fieldweek

The fieldweek associated with the 4th Asian Dendrochronological Association Conference was an excellent opportunity for education, networking, and research. The participants and group leaders worked together for five days in an area that was new to some of the group leaders and new to some of the participants which enabled us to learn about forest ecology around Kathmandu and Nagarkot, Nepal. The fieldweek was an excellent networking opportunity and the group leaders and participants bonded which strengthened international research in dendrochronology and continues to foster new research collaborations. All of the group leaders and participants had the opportunity to learn about tree-ring formation in Pinus roxburghii at 1500 masl elevation, to explore its wood anatomy, and to examine specific research questions in our field area. In the end we developed a better understanding of the stand-age structure of a stand of trees in Nagarkot, explored the erosion history from exposed roots, and investigated tree health issues on closely related sites. We found that P. roxburghii poses some dating issues with false and micro rings at this elevation, but we were still able to develop a tree-ring chronology from this species and make preliminary assessments of stand dynamics and health.     

Motile aeromonas infection of striped (grey) mullet Mugil cephalus

Infection of striped mullet (Mugil cephalus) with Aeromonas hydrophila results in an acute septicemic disease. The disease can be experimentally induced by intramuscular injection, skin or gill scarification or by the oral route using pellets purposely seeded with bacteria. The organism was isolated from the blood 1–2 days after infection and from all organs 24 hr or longer after infection. The disease is characterized by early inflammatory and proliferative changes and later necrotic changes. Enteritis and hepatic necrosis are constant findings in aeromonad disease of M. cephalus but surface lesions are not pathognomic for these infections in mullet. Death of infected fish may be attributed to bacterial toxins which cause necrosis of parenchymal organs and soft tissue structure.     

Human impact as registered in the pollen record: some results from the western Lake Constance region,Southern Germany

Pollen analytical results from a littoral profile taken in Lake Constance compared with pollen profiles from small kettle holes nearby form the basis for conclusions concerning human population density, the economy and environment from the Neolithic period to the Middle Ages. Early Neolithic human impact is implicated in a lime decline and also the expansion of beech. The late Neolithic lakeshore settlements caused a decline of elm, beech and lime and, by shifting cultivation, considerably changed the forest cover. The settlements were abandoned after less than 100 years. There were long periods without distinct human impact in the middle and towards the end of the late Neolithic period. Since at least the Late Bronze Age there has been permanent habitation in the region. Human impact was greatest in the High Medieval period and later, and was also substantial in the late La Tène and Roman periods. Distinct declines in human impact can be observed between the La Tène and Roman periods and in the Migration and Merovingian periods. In these intervals, open land and grazed oak forest were replaced by birch and later on by beech forests. The decreases in human impact are not of the same intensity in all diagrams.     

The effects of antibiotics on hemolytic behavior of red cells

Human blood was sheared between rotating polyethylene disks and plasma hemoglobin measured at intervals to produce kinetic hemolysis curves (KHC), plotted as free hemoglobin concentration vs time. The KHC produced by blood samples incubated in the presence of penicillin, streptomycin, gentamicin, and amikacin lie always below those for control samples, indicating a reduction in hemolysis; this reduction was greater as the drug concentration was increased. Explanations in terms of alterations in red cell structure were sought by several characterization tests of amikacin-loaded blood samples. Drug-localization studies demonstrated that significant fractions of the total dosage were associated with the red-cell membrane. Resistive pulse spectroscopy was used to show how amikacin affected cell size, deformability, and osmotic fragility; results were sensitive to storage age of the blood. In all cases, the effect of shearing was to reduce cell size, deformability, and osmotic fragility. Mechanisms for hemolytic protection by drugs are proposed.     

Alterations in the structure of the electrical double layer adjacent to a charged membrane arising from electromagnetically induced changes in the activity of membrane bound enzymes

Electromagnetic fields of very low amplitude have been reported to influence a number of cellular functions. Many of these effects have a high degree of frequency specificity. Herein it is suggested that some of these reported results could be explained by a fieldinduced alteration in the enzymic activity of integral membrane proteins. It is shown that such a field-induced transition from an initial nonequilibrium steady-state to a final nonequilibrium steady-state can lead to an alteration in the concentration profiles of those charged species in the cell's ambient electrolyte that comprise the so-called electrical double layer. Examples of variations in the concentration profiles of those ions that react with a membrane-bound enzyme, as well as nonreacting ionic species, are given. The modulation of such effects by systematic variations in extracellular pH and ionic strength is discussed.     

Ultrastructural evidence for an osmoregulatory effect of nikkomycin in the mite Tetranychus urticae

Histological effects of the microbial metabolite and chitin synthesis inhibitor complex Nikkomycin (AMS 0896 Bayer Leverkusen) on osmoregulatory organs of all developmental stages of Tetranychus urticae are described. The metabolite, in a concentration of 100 ppm, was applied via the nutritive plant. Mites fed for 2 to 14 days, and then were collected and immediately fixed. Two osmoregulatory organs occur in T. urticae. The Malpighian complex, differentiated only in females, shows an increased number of apical microvilli in the epithelium of the distal regions after metabolite application, thus resulting in an enlargement of the surface area. Changes in the second osmoregulatory organ, the coxal organ, after Nikkomycin application include depositions of membranous bodies in the lumen as well as in cytoplasmic vacuoles of the proximal tubule. Additionally, an increase in the luminal diameter occurs. Numerous vacuoles of different contents are observed in the cytoplasm of the distal tubule. Consequences of histological alterations in osmoregulatory organs after Nikkomycin application are discussed with special reference to the composition of salivary secretions.     

Cyproheptadine metabolites inhibit proinsulin and insulin biosynthesis and insulin release in isolated rat pancreatic islets

The contribution of drug metabolites to cyproheptadine (CPH)-induced alterations in endocrine pancreatic -cells was investigated by examining the inhibitory activity of CPH and its biotransformation products, desmethylcyproheptadine (DMCPH), CPH-epoxide and DMCPH-epoxide, on hormone biosynthesis and secretion in pancreatic islets isolated from 50-day-old rats. Measurement of (pro)insulin (proinsulin and insulin) synthesis using incorporation of ³H-leucine showed that DMCPH-epoxide, DMCPH and CPH-epoxide were 22, 10 and 4 times, respectively, more potent than CPH in inhibiting hormone synthesis. The biosynthesis of (pro)insulin was also inhibited by CPH and DMCPH-epoxide in islets isolated from 21-day-old rat fetuses. The inhibitory action of CPH and its metabolites was apparently specific for (pro)insulin, and the synthesis of other islet proteins was not affected. Other experiments showed the metabolites of CPH were active in inhibiting glucose-stimulated insulin secretion but were less potent than the parent drug in producing this effect. CPH and its structurally related metabolites, therefore, have differential inhibitory activities on insulin synthesis and release. The observation that CPH metabolites have higher potency than CPH to inhibit (pro)insulin synthesis, when considered with published reports on the disposition of the drug in rats, indicate that CPH metabolites, particularly DMCPH-epoxide, are primarily responsible for the insulin depletion observed when the parent compound is given to fetal and adult animals.Abbreviations CPH cyproheptadine - CPH-epoxide cyproheptadine-10-11-epoxide - DMCPH desmethylcyproheptadine - DMCPH-epoxide desmethylcyproheptadine-10,11-epoxide - HPLC high-performance liquid chromatography - KBB Krebs biocarbonate buffer Recipient of a Society of Toxicology Predoctoral Research Fellowship.Present address: Department of Biochemistry, The University of Hong Kong, Hong Kong.     

The Lipid Peroxidation Product, 4-Hydroxy-2-trans-Nonenal, Alters the Conformation of Cortical Synaptosomal Membrane Proteins

Abstract: Alzheimer's disease (AD) is widely held to be a disorder associated with oxidative stress due, in part, to the membrane action of amyloid β-peptide (Aβ). Aβ-associated free radicals cause lipid peroxidation, a major product of which is 4-hydroxy-2- trans -nonenal (HNE). We determined whether HNE would alter the conformation of synaptosomal membrane proteins, which might be related to the known neurotoxicity of Aβ and HNE. Electron paramagnetic resonance spectroscopy, using a protein-specific spin label, MAL-6(2,2,6,6-tetramethyl-4-maleimidopiperidin-1-oxyl), was used to probe conformational changes in gerbil cortical synaptosomal membrane proteins, and a lipid-specific stearic acid label, 5-nitroxide stearate, was used to probe for HNE-induced alterations in the fluidity of the bilayer domain of these membranes. Synaptosomal membranes, incubated with low concentrations of HNE, exhibited changes in protein conformation and bilayer order and motion (fluidity). The changes in protein conformation were found to be concentration- and time-dependent. Significant protein conformational changes were observed at physiologically relevant concentrations of 1–10 µ M HNE, reminiscent of similar changes in synaptosomal membrane proteins from senile plaque- and Aβ-rich AD hippocampal and inferior parietal brain regions. HNE-induced modifications in the physical state of gerbil synaptosomal membrane proteins were prevented completely by using excess glutathione ethyl ester, known to protect neurons from HNE-caused neurotoxicity. Membrane fluidity was found to increase at higher concentrations of HNE (50 µ M ). The results obtained are discussed with relevance to the hypothesis of Aβ-induced free radical-mediated lipid peroxidation, leading to subsequent HNE-induced alterations in the structure and function of key membrane proteins with consequent neurotoxicity in AD brain.     

On the integrated interpretation of indirect site ordinations: a case study using semi-arid vegetation in southeastern Spain

The need for rigorous methods of interpreting indirect site ordinations is discussed and the problem of oblique habitat and phytosociological trends is emphasized. A sequential approach, termed integrated interpretation, is introduced to overcome this problem. It first involves a technique termed rotational correlation a linear form of trend surface analysis, which locates the best fit between a habitat variable and the coordinates of a pluridimensional ordination. The coordinates at positions of best fit are then used to produce two-way site-species tables (seriation arrays) which summarize floristic variation in relation to each major habitat trend. The seriation arrays can also be used to identify groups of differential species. Integrated interpretation is demonstrated using semi-arid vegetation from Murcia Province, SE Spain. A two-axis site ordination of vegetation data by non-metric multidimensional scaling is shown to have two oblique trends related to aspect-induced topoclimates and types of past anthropogenic disturbance. Rotation of the configuration to maximum linear correlation achieves very high levels of explanation for each factor. Rotated ordination coordinates from the correlation analysis are used to obtain two seriation arrays and floristic noda which relate directly to the two underlying habitat trends. A floristic discontinuity is revealed on the topoclimate continuum and it is hypothesized that temperature conditions are a major determinant of floristic composition, but that moisture partly determines vegetational cover and phytomass. Several patterns of past cultivation are detected and associated with five main kinds of geomorphological unit, together with some evidence that the rate of succession is partly determined by topoclimate. The integrated approach to interpretation is compared with visual methods and other multivariate techniques. A case is made for increased interpretational rigour in site coordinate studies, especially the discontinuation of trend-seeking using individual unrotated ordination axes.Nomenclature of vascular plants follows Tutin et al. (1964–1980) Flora Europaea 5 Vols. Cambridge University Press, Cambridge. Nomenclature of syntaxa follows Rivas-Goday & Rivas-Martinez (1967).I am indebted to J. A. Michel, Dr M. A. Abdelrahman and Monica M. Dargie for field assistance. Field discussion with Dr R. L. Wright, Dr M. P. Austin and Professor F. Esteve Chueca was most helpful; the latter assisted with confirmation of vascular plant voucher specimens. Non-vascular taxonomy was determined by Dr C. Humphries (mosses and one alga) and Dr O. L. Gilbert (lichens). An anonymous referee suggested an approximation of the analytical solution to rotational correlation, and Dr N. R. J. Fieller assisted with its confirmation. The project was assisted by a grant from the University of Sheffield Research Fund.     

Die Anwendung einer ‘deduktiven Methode syntaxonomischer Klassifikation’ bei der Bearbeitung der strassenbegleitenden Pflanzengesellschaften Nordostböhmens

Zusammenfassung In der vorgelegten Arbeit wurde die sogenante deduktive Klassifikationsmethode der anthropogenen Pflanzengesellschaften behandelt. Diese Methode geht vom System der höheren Vegetationseinheiten der Braun-Blanquet Schule aus. Sie ermöglicht die syntaxonomische Bearbeitung zahlreicher anthropogener Gesellschaften unserer Kulturlandschaft, die nur aus Arten mit breiterer ökologischer und zönologischer Amplitude zusammengesetzt sind, und zwar ohne unerwünschte Verwechslung der Bestimmungsmerkmale einzelner Rangstufen des Systems (Klassen-, Ordnungs-, Verbands- und Assoziationskenn-und trennarten). Die Grundprinzipien der Methode wurden schon früher von Kopecký & Hejný (1971, 1973, 1974) und Kopecký (1976) erläutert. Die vorliegende Arbeit bringt eine präzisierte Auslegung der Methode auf Grund neuer Erfahrungen, die bei der Bearbeitung der spontan entstandenen strassenbegleitenden Gesellschaften derMolinio-Arrhenatheretea Tx. 1937 in Nordostböhmen gewonnen wurden. Aus dem reichen Aufnahmematerial werden nur einige Aufnahmen der Basalgesellschaften mitAlopecurus pratensis und der von ihnen abgeleiteten Derivatgesellschaften mitDactylis glomerata undAgropyron repens fur die anschauliche Demonstration der Methode beigegeben (Tab. 1 und 2). Die Aufnahmen der übrigen Gesellschafts-typen werden in einer anderen Arbeit (Kopecký 1978) veröffentlicht.

---

Summary Use of a so-called deductive method in syntaxonomic classification of roadside plant communities in NE Bohemia.The present paper explains the so-called deductive method of syntaxonomic classification of plant communities, derived from the system of syntaxa of higher rank of the Braun-Blanquet approach. This method enables the synthesis of vegetations units of the varied anthropogenic plant communities in the man-made landscape, and their arrangement within the existing system, without changing the classification and determination criteria of both the higher and lower syntaxa in this system. Basic principles of this method have been outlined earlier by Kopecký & Hejný (1971, 1973, 1974) and Kopecký (1976). Following the newly obtained data and experience, this paper brings further details and more precise explanation of the method. Recently, the deductive method has been applied to the classification of turf communities which spontaneously develop along the roads in NE Bohemia. In order to illustrate the principles of the method, selected relevés of basal communities withAlopecurus pratensis (Table 1), and respective communities derived from these basal communities (Table 2) are presented. A complete set of vegetation relevés of all other roadside communities will be published elsewhere (Kopecký 1978).

Die wissenschaftlichen Pflanzennamen sind nach Rothmaler et al. (1966) angeführt.