ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Coleoptera  (31)
  • calcium  (26)
  • Springer  (57)
  • PANGAEA
  • 1995-1999
  • 1985-1989  (57)
  • 1980-1984
  • 1940-1944
  • 1985  (57)
Collection
Publisher
Years
  • 1995-1999
  • 1985-1989  (57)
  • 1980-1984
  • 1940-1944
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 37 (1985), S. 241-245 
    ISSN: 1570-7458
    Keywords: Coleoptera ; Bruchidae ; Callosobruchus ; cowpea weevil ; egg recognition ; oviposition deterrents
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Plusieurs expériences ont été réalisées pour déterminer pour quelles raisons les femelles de Callosobruchus maculatus évitent de pondre sur les graines portant des oeufs. La répulsion a été associée à l'oeuf lui-même et non à une autre activité de l'adulte sur la graine. Des stimuli tant chimiques que physiques (tactiles) ont semblé impliqués dans la découverte des oeufs; la substance répulsive était plus soluble dans le méthanol que dans l'éther ou l'eau. Contrairement à des études antérieures sur C. chinensis, nous avons observé que les femelles n'étaient pas dissuadées de pondre sur des graines exposées préalablement à de fortes densités de mâles.
    Notes: Abstract Several experiments were conducted to determine the mechanism by which ovipositing cowpea weevils, Callosobruchus maculatus (F.), avoid egg-laden seeds. Deterrence was associated with the egg itself and not with other adult activities on the host. Both chemical and physical (tactile) stimuli appear to be involved in egg recognition; the chemical deterrent was more soluble in methanol than in ether or water. Contrary to a previous study using C. chinensis (L.), we found that females were not deterred from ovipositing on seeds that had been exposed to high densities of males.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 39 (1985), S. 81-84 
    ISSN: 1570-7458
    Keywords: induced change ; induced resistance ; chemical change ; feeding ; herbivore ; feeding tests ; feeding preferences ; Coleoptera ; Chrysomelidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les choix alimentaires d'un groupe de chrysoméles spécialistes ou généralistes a été étudié en utilisant 3 méthodes: plantes entières, feuilles coupées, rondelles de feuilles. Les méthodes utilisées out eu un effet très significatif sur les préférences relatives des chrysomèles du maïs, du haricot et de la courge. Dans quelques cas le seuil de signification statistique pour un choix particulier a été modifié par la méthode utilisée et dans d'autres cas l'ordre de préférence a été totalement inversé. Les choix alimentaires des spécialistes ont été moins affectés par la méthode utilisée que pour les espèces les plus généralistes. Il y a eu aussi un effet plus important des différences entre les méthodes rondelle de feuilles et feuille entière qu'entre feuille entière et plante entière. Les changements chimiques induits dans les plantes par les dégâts sont probablement très répandus et les chercheurs devraient en tenir compte quand ils programment et interprètent des expériences sur les préférences alimentaires.
    Notes: Abstract Feeding preferences of a group of specialist and generalist chrysomelid beetles were examined using three test methods: whole plants, excised leaves and leaf discs. Method of testing had a very significant effect on relative preferences of the beetles for corn, bean and squash. In some cases the level of statistical significance for a particular preference was affected by test methodology and in other cases the direction of preference was reversed altogether. The feeding preferences of the specialist beetle species were less affected by test method than were the more generalist species. There was also a much greater effect of the difference in test method between the disc test and whole leaf test than between the whole leaf test and whole plant test. Chemical changes in plants induced by damage are probably quite widespread in plants and investigators should take this into account when designing and interpreting tests of insect feeding preference.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 37 (1985), S. 113-121 
    ISSN: 1570-7458
    Keywords: Hypera postica ; alfalfa weevil ; allozyme analysis ; Coleoptera ; Curculionidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les allozymes d'Hypera de l'est des USA (Beltsville, Maryland; Washington Co., Illinois), de l'ouest des USA (Logan et St Georges, Utah) et ‘égyptiens’ (Yuma, Arizona; Westmorland, Californie) ont été analysés par électrophorèse sur gel d'acrylamide. L'étude a porté sur 22 loci de 12 enzymes (ACPH, ADH, AMY, AO, EST, GOT, G-6PDH, MDH, ME, SOD, TYR, XDH). L'hétérozygotie moyenne de la population était 0.231, avec une moyenne de loci polymorphes de 0.536. La distance génétique moyenne de l'ensemble des populations était de 0.033 et l'indice de fixation de 0.024. Des loci caractéristiques ont été trouvés qui pourraient permettre de distinguer les Hypera occidentaux des orientaux et des ‘égyptiens’. La faible distance génétique entre les Hypera orientaux et ‘égyptiens’ suggère qu'ils appartiennent à la même souche et sont certainement différents des occidentaux. A partir de cela et d'autres éléments, nous concluons que tous les Hypera des USA sont H. postica Gyllenhal et que l'utilisation d'H. brunneipennis Boheman pour désigner les Hypera ‘égyptiens’ d'Amérique du Nord doit être abandonnée.
    Notes: Abstract Allozyme profiles of eastern weevils (Beltsville, Maryland; Washington Co., Illinois), western weevils (Logan and St. George, Utah), and Egyptian weevils (Yuma, Arizona; Westmorland, California) were compiled by acrylamide gel electrophoresis. Twenty-two gene loci from 12 enzymes (ACPH, ADH, AMY, AO, EST, GOT, G-6PDH, MDH, ME, SOD, TYR, XDH) were analyzed. Mean heterozygosity of these populations was 0.231, with an average proportion of polymorphic loci of 0.536. The mean genetic distance of all weevil populations was 0.033 and the fixation index was 0.024. Diagnostic loci were found which could distinguish western weevils from eastern and Egyptian weevils. The small genetic distance between the eastern and Egyptian weevils suggests that they may be the same strain and are certainly different from the western weevil strain. Based on this and other evidence, we conclude that all weevil strains in the United States are Hypera postica (Gyllenhal), and that the use of H. brunneipennis (Boheman) for the Egyptian alfalfa weevil of North America should be discontinued.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 37 (1985), S. 229-233 
    ISSN: 1570-7458
    Keywords: alfalfa weevil ; Coleoptera ; Curculionidae ; Hypera postica ; mutation ; vestigial-wing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Des H. postica aux ailes postérieures vestigiales ont été découverts dans une population de Wageningen (Pays Bas) et deux des USA—une lignée orientale de Beltsville (Maryland) et une lignée de H. brunneipennis d'Atascadero (Californie). Ce mutant était absent de 23 autres populations examinées aux USA: 3 de l'est, 7 de l'ouest et 13 de H. brunneipennis. Cette mutation est due à un gène dominant antosomal avec aile normale comme récessif. Le gêne mutant peut être transféré des lignées orientales aux lignées occidentales. Le caractère aile courte peut être pratique pour les manipulations génétiques destinées à maîtriser les populations d'H. postica.
    Notes: Abstract Alfalfa weevils (Hypera postica (Gyllenhal)) with vestigial hind wings were discovered in a population from Wageningen, the Netherlands, and two populations from the United States—an eastern weevil strain from Beltsville, Maryland and an Egyptian weevil strain from Atascadero, California. Such a mutant was absent from 23 other populations surveyed in the United States—three from eastern, seven from western, and 13 from Egyptian weevil strains. This mutation is due to a dominant autosomal gene with normal-wing individuals as recessive. The mutant gene can be transferred from eastern weevil to the western weevil strain. The short-wing trait may be useful for genetic manipulation to control the alfalfa weevil.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 39 (1985), S. 223-232 
    ISSN: 1570-7458
    Keywords: Onitis alexis ; Coleoptera ; Scarabaeinae ; dung beetle ; crepuscular flight ; superposition eyes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé L'examen a porté sur le rôle de l'intensité lumineuse et de la température sur l'incitation au vol chez Onitis alexis. Le vol en lumière naturelle est fortement synchronisé, avec les deux tiers des adultes qui s'envolent en 10–12 min. Sur six vols pour différents jours, le moment moyen d'envol variait de 13 min, mais l'envol moyen avait lieu à une intensité lumineuse déterminée. La valeur absolue de l'intensité lumineuse paraît ainsi un signal crucial dans la détermination et l'incitation au vol. Le moment d'envol se maintient à cette intensité quand le crépuscule est artificiellement avancé jusqu'à 8 min environ. Cependant, quand le crépuscule est rendu encore plus précoce, l'envol moyen se produit à des intensités plus basses et est étalé. Ceci peut être interprété comme un chevauchement de la période des intensités lumineuses favorables à l'envol avec le rythme circadien qui conduit les bousiers à la surface. Aucun adulte ne vole quand il y a maintien de lumière constante ou d'obscurité à l'heure du crépuscule. En présence de crépuscule constant, les réponses sont hétérogènes, et, bien que le moment médian d'envol ne soit retardé que de 3 min, par rapport aux témoins, l'incitation à l'envol est étalée sur une période plus longue. Avec des températures au sol de 20–22 °C, plus de 90% des adultes s'envolent. Le pourcentage diminue avec la température, et moins de 10% s'envolent à 16–17 °C.
    Notes: Abstract The role of light intensity and temperature in determining the onset of flight in the crepuscular dung beetle Onitis alexis Klug (Coleoptera: Scarabaeidae) was examined. Flight under natural light was highly synchronized, with two-thirds of the beetles that flew flying over a period of 10–12 min. In six flights on different days, the mean time of onset varied by up to 13 min, but mean onset occurred at fixed light intensity. Absolute light intensity therefore appears to be a vital cue in determining flight onset. Mean onset remained at this intensity when dusk was advanced artificially by up to about 8 min. However, when dusk was brought further forward, mean flight occurred at lower intensities and onset of flight took place over a longer period. This is interpreted as an overlapping of the period of light intensities suitable for flight with the circadian rhythm that brings the beetles to the surface. No beetles flew when kept under constant bright light or in the dark during the dusk period. Under conditions of constant dusk, the beetles appeared uncoordinated and, although the median time of onset of flight was only 3 min later than in the control flight, onset of flight was spread out over a much longer period. At soil temperatures of 20–22 °C, over 90% of the beetles flew. This percentage decreased with decreasing temperature, and less than 10% flew at temperatures of 16–17 °C.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 37 (1985), S. 123-127 
    ISSN: 1570-7458
    Keywords: Coleoptera ; Carabidae ; Poecilus cupreus ; larva ; starvation ; digestion ; enzyme-linked immunosorbent assay
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Mit eine quantitativen enzymabhängigen Immunoabsorptionstest wurde immunoreaktives Material aus Beutetieren als Eiweissgehalt (IRM/P) in Larven eines polyphagen räuberischen Carabiden, Poecilus cupreus, bestimmt. Wir bestimmten den Beuteverzehr und die Geschwindigkeit des IRM/P Abbaus bei Larven, die während verschiedener Zeit gehungert hatten. Der Beuteverzehr nahm exponentiell zu über 7 Tage Hunger. Die Geschwindigkeit des Beute- IRM/P Abbaus schien logarithmisch. Die Beuteaufnahme nahm fast zwanzigfach zu über 7 Tage Hunger von 2.7 ng auf 50.2 ng IRM/P/10 Mikroliter Larvenextrakt. Der grösste Teil der Verdauung erfolgte am zweiten bis dritten Tag nach der Nahrungsaufnahme, unabhängig von der verdauten Menge. Das Niveau 4 Tage nach der Fütterung zeigte, dass Larven, die vorgängig 7 Tage gehungert hatten, 5.0 ng IRM/P/10 Microliter Extrakt zurückhielten; dies war mehr als die Aufnahmemenge nichthungernder Larven. Die Verdauungsgeschwindigleit nahm zu mit der Dauer des Hungerns, doch wurde auch mehr Beute im Nahrungskanal zurückgehalten.
    Notes: Abstract Prey antigen levels were determined by a quantitative enzyme-linked immunosorbent assay in larvae of a carabid predator, Poecilus cupreus L. under laboratory conditions. We determined prey consumption and rate of prey protein decay in larvae having starved for different periods. Prey consumption increased exponentially over 7 days of starvation. The rate of prey immunoreactive material decay seemed to be logarithmic, similar in larvae which had starved for different periods. Most of the digestion took place in the first 3 days period after feeding, irrespective of the amounts ingested. The rate of decay increased with increasing period of starvation. There were also signs of food retention in the alimentary canal in larvae which starved longer.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 1570-7458
    Keywords: Coleoptera ; Bruchidae ; diapause reproductrice ; inflorescence ; Vigna unguiculata ; activité sexuelle mâle ; ovogenèse ; ponte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Summary Bruchidius atrolineatus (Pic) is a widely distributed bruchid in the Sahelian zone which shows a reproductive diapause during the dry season and part of the rainy season. Diapausing females do not produce vitellogenin and their ovaries are reduced to the germarium. Spermatogenesis is very much reduced and male accessory glands are inactive. When these insects were placed in the presence of inflorescences of Vigna unguiculata which were renewed daily, the reproductive diapause of both males and females was interrupted after 15–20 days. Vitellogenesis occurred in the females and spermatogenesis increased in the males whilst their accessory glands became functional. When diapausing bruchids, found in stores of on V. unguiculata seeds during the dry season, were placed near the host plant's inflorescences, diapause was also terminated. In all cases, diapause was not interrupted when the insects were offered dry pods of V. unguiculata in a water-saturated atmosphere. The pollen, which is hardly eaten by this bruchid, did not seem to stimulate termination of diapause. Sensory stimulations derived from the flowers or/and nutritional factors may be the cause of the development of the reproductive organs. After termination of the diapause the males showed normal sexual activity whereas female fecundity was rather low, at least in our experimental conditions. This type of reproductive regulation allows this sahelian bruchid to resume its sexual activity when the host plant's flowers appear in the field at the end of the rainy season. Then the beetles lay their eggs on the pods as soon as the pods are developed.
    Notes: Abstract Bruchidius atrolineatus (Pic) présente en zone sahélienne une diapause reproductrice durant la saison sèche et une partie de la saison des pluies. Les femelles diapausantes ne produisent pas de vitellogénine et le germarium des ovarioles est seul développé. Chez les mâles la spermatogenèse est très ralentie et les glandes annexes sont inactives. Lorsque les insectes diapausants sont placés en présence d'inflorescences de Vigna unguiculata Walp, leurs organes reproducteurs deviennent fonctionnels après un temps de latence de 15 à 20 jours. Il n'y a par contre aucune levée de la diapause chez des bruches placées en présence de gousses sèches de V. unguiculata dans une atmosphère saturée. Des informations sensorielles issues des pièces florales ou (et) des facteurs nutritionnels sans doute liés a la consommation de nectar semblent être à l'origine de cette levée de la diapause. Le pollen fort peu consommé n'a par contre aucun rôle. Cette régulation du cycle reproducteur de B. atrolineatus par les inflorescences de V. unguiculata permet l'émission des oeufs dès que les gousses commencent à se former à la fin de la saison des pluies.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 39 (1985), S. 61-71 
    ISSN: 1570-7458
    Keywords: Dacus tryoni ; Tephritidae ; Diptera ; fruit flies ; oviposition ; egg laying ; behaviour ; taste receptors ; chemoreceptors ; stimulant ; deterrent ; fructose ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Des mouches fruitières gravides du Queensland (Dacus tryoni), confinées au laboratoire dans des chambres d'oviposition sont stimulées par la présence de β-D(-)fructose, à pondre significativement plus d'oeufs dans un substrat gélosé. Ce composé est un véritable stimulant d'oviposition, accroissant le nombre d'oeufs déposés par mouche, plutôt que simplement localisant l'oviposition dans les substrats le contenant. Le fructose est effectif seulement lorsqu'il est accessible aux récepteurs gustatifs tarsaux et labelliaux et, apparement, agit en stimulant de plus fréquentes insertions de l'ovipositeur dans le substrat; le contact du fructose avec uniquement l'ovipositeur inséré, n'accroît pas l'oviposition. Le seuil de concentration pour obtenir une stimulation par le fructose est de 4 mM; la résponse maximale se produit à 50 mM et au delà, auxquelles concentrations l'oviposition est augmentée d'un facteur 6 par rapport au témoin, qu'il y ait ou non possibilité de choix de substrat. Le sucrose (testé à 100 et 1 000 mM) et le D-glucose (testé à 100 et 500 mM) ne stimulent pas l'oviposition chez D. tryoni. Le fructose favorise fortement l'oviposition grâce aux trous existants dans une surface impénétrable, et dans les conditions naturelles, D. tryoni l'utilise probablement comme un marqueur pour localiser les ruptures dans la peau des fruits, où l'insertion est plus facile. La présence de chlorure de calcium molaire dans la gélose fructose inhibe fortement l'oviposition, même lorsqu'il est inaccessible aux récepteurs gustatifs tarsaux et labelliaux. Le chlorure de sodium molaire n'est pas inhibiteur. Les ions calciums déploient apparemment leur effet inhibiteur par l'intermédiaire de récepteurs gustatifs localisés sur l'ovipositeur.
    Notes: Abstract Gravid Queensland fruit flies (Dacus tryoni) are stimulated by the presence of β-D(-) fructose to lay significantly more eggs in an agar substrate. Fructose is only effective when accessible to the tarsal and/or labellar gustatory sensilla; it greatly increases oviposition through holes in an impenetrable membrane. Threshold for the fructose effect is 4 mM, maximal response being at 50 mM and above. Sucrose and glucose are not oviposition stimulants for D. tryoni. In the field situation D. tryoni probably uses fructose as a marker to locate breaks in the skin of ripe fruit, where insertion of the ovipositor is easier. The flies are deterred from ovipositing in fructose agar by the presence of molar calcium chloride, even when this is inaccessible to the tarsal and labellar gustatory sensilla. Molar sodium chloride is not inhibitory. Calcium ions apparently exert their inhibitory effect via gustatory sensilla located on the ovipositor.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Methods in cell science 9 (1985), S. 83-93 
    ISSN: 1573-0603
    Keywords: keratinocytes ; human ; epidermis ; serum-free ; calcium ; differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Methods are described for serum-free culture of human epidermal keratinocytes derived from neonatal foreskin tissue. Cultures are initiated, stored frozen, and returned to active growth, all with bovine pituitary extract as the only undefined supplement. Clonal growth assays are then performed in a biochemically defined medium. The degree of stratification and differentiation in the defined medium (and also with pituitary extract) is controlled by the extracellular calcium ion concentration.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 41 (1985), S. 997-1001 
    ISSN: 1420-9071
    Keywords: Myosin light chain kinase ; calcium ; c-AMP ; calmodulin ; smooth muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 41 (1985), S. 1048-1051 
    ISSN: 1420-9071
    Keywords: Na, K-ATPase ; calcium ; calmodulin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effect of calcium on Na, K-ATPase activity of rat brain homogenates and its modification by the chelating agent EDTA has been investigated. In the absence of EDTA, free calcium (approximately 10−6mol/l) stimulates Na,K-ATPase activity; in the presence of EDTA the same concentration of free calcium is without effect on the enzyme. In the absence of EDTA the stimulation by calcium of Na,-K-ATPase activity is enhanced by the additional presence of calmodulin but in the presence of EDTA, even when calmodulin is added to excess, calcium still fails to stimulate the enzyme. The possibility that EDTA interferes with an interaction between a calcium-calmodulin complex and Na,K-ATPase is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    ISSN: 1420-9071
    Keywords: Smooth muscle ; calcium ; myosin light chain kinase ; regulation of contraction ; ATPase ; mechanics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The contraction induced by a Ca2+-independent myosin light chain kinase (MLCK-) was characterized in terms of isometric force (Fo), immediate elastic recoil (SE), unloaded shortening velocity (Vus), shortening under a constant load and ATPase activity of chemically skinned smooth muscle preparations. These parameters were compared to those measured in a Ca2+-induced contraction to assess the nature of cross bridge interaction in the MLCK-induced contraction. Fo developed in chicken gizzard fibers as well as SE were similar in contractions elicited by either agent. Vus in the contraction induced by MLCK-(0.36 mg/ml) was similar though averaged 39.3±8.9% less than Vus induced by Ca2+ (1.6x10−6M) in the control fibers. Addition of Ca2+ (1.6x10−6M) to a contraction induced by MLCK-resulted in small increases in both Fo and Vus. Shortening under a constant load was similar for both types of contractions. The contraction induced by MLCK-was accompanied by an increased rate of ATP hydrolysis. The MLCK-induced contraction is thus kinetically similar though not identical to a contraction induced by Ca2+. We conclude that with respect to actin-myosin interaction, MLCK- and Ca2+-induced contractions are similar.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 41 (1985), S. 1020-1025 
    ISSN: 1420-9071
    Keywords: Smooth muscle energetics ; light chain phosphorylation ; crossbridges ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Conclusion On the basis of measurements of the high energy phosphate usage associated with different mechanical states, as well as the degree of myosin light chain phosphorylation and mechanical properties, information has been gained concerning the existence and regulation of different crossbridge states in smooth muscle. Although incomplete, a general operational scheme is shown in figure 5. At very low intracellular calcium concentrations, actin and myosin are dissociated, as shown by a loss of resistance to stretch in resting muscles. At somewhat higher intracellular calcium concentrations in atonic, resting muscles, crossbridges can attach and be manifest mechanically as an increased resistance to stretch without ATP-driven crossbridge cycling and active force production. When the muscle is activated, intracellular calcium increases further, the light chains of myosin are phosphorylated through the calcium-calmodulin activation of myosin light chain kinase, actin-activated myosin ATPase activity increases and crossbridges cycle. Calcium also appears to modulate the ATPase activity and the rate of cycling of the phosphorylated crossbridge. The crossbridge cycling rate is highest during force development and slows with time as maximum isometric force is maintained reflecting a change in the rate at which phosphorylated crossbridges cycle. This may result from a decrease in the intracellular free calcium concentration with continued stimulation. During relaxation, the intracellular calcium concentration decreases, there is net dephosphorylation of the myosin light chains, the rate at which phosphorylated crossbridges cycle slows further with a gradual return to the attached, but non-cycling state or the detached state.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 41 (1985), S. 516-519 
    ISSN: 1420-9071
    Keywords: Coleoptera ; chemical defense ; steroids ; pregnanes ; isoprenoids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The defensive anal effluent discharged bySilpha americana in response to disturbance contains a mixture of steroids stemming from a glandular annex of the rectum. The compounds have been characterized as 15β-hydroxyprogesterone (1, principal component), 5β-pregnan-15β-ol-3, 20-dione (2), 5β-pregnan-3α, 15β-diol-20-one (3), 5β-pregnan-7β, 15β-diol-3,20-dione (4), 5β-pregnan-3α, 7β, 15β-triol-20-one (5), 5β-pregnan-16α-ol-3,20-dione (6), and 5β-pregnan-3α, 16α-diol-20-one (7), none previously found in insects. Bioassays with jumping spiders showed compounds1 and6 to be feeding deterrents at the 1 μg level.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 66 (1985), S. 111-116 
    ISSN: 1573-4919
    Keywords: Adenosine triphosphatase ; Na+ ; K+ ; catecholamines ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary The interaction of noradrenaline, various cation chelators and calcium on Na+, K+-ATPase from rat cerebral cortex plasma membranes was studied. It was shown that chelation of inhibitory cations by EGTA, EDTA and dipyridyl activated Na+, K+-ATPase to the same extent as noradrenaline but at higher concentrations; increasing concentrations of EGTA depressed the activation by noradrenaline; calcium in the form of a calcium-EGTA buffer depressed Na+, K+-ATPase at physiological concentrations; the inhibition of Na+, K+-ATPase by calcium is dependent on the magnesium concentration in the assay and the inhibition by calcium was partially reversed by noradrenaline.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 66 (1985), S. 145-149 
    ISSN: 1573-4919
    Keywords: calcium ; cyclic GMP ; gonadotropin releasing hormone ; guanylate cyclase ; manganese
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary Gonadotropin releasing hormone enhanced guanylate cyclase [E.C.4.6.1.2] two- to threefold in pituitary, testis, liver and kidney. Dose response relationships revealed that at a concentration of 1 nanomolar, gonadotropin releasing hormone caused a maximal augmentation of guanylate cyclase activity and that increasing its concentration to the millimolar range caused no further enhancement of this enzyme. There was an absolute cation requirement for gonadotropin releasing hormone's enhancement of guanylate cyclase activity as there was no increase without any cation present. Gonadotropin releasing hormone could increase guanylate cyclase activity with either calcium or manganese in the incubation medium but more augmentation was observed with manganese. The data in this investigation suggest that guanylate cyclase may play a role in the mechanism of action of gonadotropin releasing hormone.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 67 (1985), S. 145-150 
    ISSN: 1573-4919
    Keywords: calcium ; harmaline ; smooth muscle ; sodium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary The effect of changing the extracellular concentration of both Na+ and K+ on the longitudinal muscle of the guinea-pig ileum was studied in the presence and absence of harmaline. A decrease in extracellular Na+ concentration was found to produce a dose-dependent contractile response, which may suggest the existence of a Na...Ca exchange mechanism in this muscle. Harmaline (2 × 10−4 M) was found to reversibly inhibit this contraction and was also found to selectively block the tonic component of high-K induced contradictions. In view of the fact that harmaline is a non-competitive inhibitor of Ca-induced contractions (Hider et al., Europ. J. Pharmacol., 71, 87, 1981), the action of harmaline was interpreted as being a specific inhibitor of the Na... exchange mechanism, binding specifically to Na+ coordination sites.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    Springer
    Molecular and cellular biochemistry 68 (1985), S. 115-120 
    ISSN: 1573-4919
    Keywords: pyruvate kinase isoenzymes ; pancreatic islets ; kinetic and immunological studies ; calcium ; alanine ; phenylalanine ; fructose bisphosphate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract To determine which of the major isoenzymes of pyruvate kinase pancreatic islet pyruvate kinase most resembled, it was compared to pyruvate kinase from other tissues in kinetic and immunologic studies. The pattern of activation by fructose bisphosphate and the patterns of inhibition by alanine and phenylalanine were most similar to those of the M2 isoenzyme from kidney and were dissimilar to those of the isoenzymes from skeletal muscle (type M1) and liver (type L). The islet pyruvate kinase was inhibited by anti-M1 pyruvate kinase serum (which crossreacts with the M2 isoenzyme), but not by anti-L pyruvate kinase. These results are most consistent with islets possessing predominantly, if not exclusively, the M2 isoenzyme of pyruvate kinase. We previously showed that rat pancreatic islet cytosol contains protein kinases that can catalyze a calcium-activated phosphorylation of an endogenous peptide that has properties, such as subunit molecular weight and isoelectric pH, that are identical to those of the M2 and M, isoenzymes of pyruvate kinase, and that islet cytosol can catalyze phosphorylation of muscle pyruvate kinase. In the present study it was shown that incubating islet cytosol with ATP under conditions known to permit phosphorylation and inhibition of liver pyruvate kinase did not affect the islet pyruvate kinase activity. It is concluded that phosphorylation of the islet pyruvate kinase has no immediate effect on enzyme activity.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    ISSN: 1573-1561
    Keywords: Chiral semiochemicals ; pheromones ; enantiomeric composition ; Ips pini ; Coleoptera ; Scolytidae ; Apis mellifera ; Hymenoptera ; apidae ; Cryptolestes Ferrugineus ; Cucujidae ; acetyl lactate diastereoisomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A method is described for determining the enantiomeric composition of chiral alcohols, lactones, and hydroxy acids in quantities ranging from 25 ng to 10 μg. Derivatization of the substance with chirally pure acetyl lactate, followed by splitless capillary gas chromatography, enables enantiomeric determinations to be made within 1–3% of the actual value. This technique was applied in the determination of semiochemical inIps pini (Say),Apis mellifera (L.), andCryptolestes ferrugineus (Stephens). The results indicate that considerable variability exists within populations of some insects in the composition of their chiral semiochemicals, whereas others produce substances of constant composition.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    ISSN: 1573-1561
    Keywords: Isoflavonoids ; structure-activity relationships ; insect feeding-deterrent activity ; Costelytra zealandica ; Coleoptera ; Scarabaeidae ; stereochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A number of naturally occurring isoflavonoids of differing substitution patterns and oxidation states have been tested for feeding deterrent activity in a bioassay with larvae ofCostelytra zealandica White. The most active deterrents, which reduced feeding significantly at 0.2-1.0 μg/g, are those compounds containing a ring B-fused cycloprenoid moiety. The least active compounds were highly oxidized coumestans and isoflavones. The ring B-fused cyclic isoprenoid moiety and the presence of a 2'-oxy function appear to be structural features important for high activity. It is suggested that the feeding deterrent activity of isoflavonoids relates to their stereochemistry and that the most active compounds have or can adopt a similar nonplanar molecular shape with a similar arrangement of polar and lipophilic groups.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 86 (1985), S. 113-125 
    ISSN: 1432-1424
    Keywords: epithelial monolayers ; MDCK cells ; tight junctions ; calcium ; biosynthesis of junctions ; junctional assembly ; apical/basolateral polarization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Synthesis and assembly of tight junctions are studied in monolayers of MDCK cells plated at a density sufficient for confluence, allowed to attach for 1 hr, and transferred to fresh media without cells containing or not Ca2+, 20 hr later, while monolayers with Ca2+ have fully developed junctions that confer an electrical resistance across of 346±51 Ω cm2, those without Ca2+ have a negligible resistance. If at this time Ca2+ is added, junctions assemble and seal with a fast kinetics, that can be followed through the development of electrical resistance, penetration of ruthenium red, and electron microscopy. Drugs that impair synthesis, maturation and transport of proteins (cycloheximide, tunicamycin, monensin) indicate that protein components are synthesized early upon plating, do not seem to require N-glycosylation, and are stored in the Golgi compartment. Upon addition of Ca2+ they are transferred to the membrane with the participation of microfilaments but not of microtubules. These components seem to insert directly in the position they occupy in the strands, and the cell circles its perimeter with one strand as early as 15 min, even if in some segments it only consists of a row of particles. New strands develop in association with previous ones, and the pattern completes in 4 to 6 hr. Ca2+ is required for the maintenance of the assembly and also for the sealing with neighboring cells. These processes cannot occur below 25°C. Serum is not required. Polarized distribution of intramembrane particles (IMP) in apical and basolateral regions follows the same time course as junction formation, in spite of the fence constituted by those strands that are already assembled. This suggests that IMP do not redistribute by lateral displacements in the plane of the membrane, but by removal and insertion in the apical and basolateral domains.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 85 (1985), S. 269-280 
    ISSN: 1432-1424
    Keywords: cell fusion ; electrofusion ; dielectrophoresis ; calcium ; magnesium ; membrane lipid ; lymphoma cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Mouse leukemic lymphoblasts (L5178Y) brought into close contact by dielectrophoresis underwent cell fusion following the application of electrical pulses in the presence of electrolytes. The electrically fused cells became spherical after switching off the dielectrophoretic field. Fusion between a cell vitally stained with Janus Green and that with Neutral Red resulted in the homokaryon with a mixed color. Intracellular potentials simultaneously recorded from the two cells located on both sides of the homokaryon were identical. The fusion efficiency was remarkably dependent upon temperature, displaying a discontinuity at about 11°C in the Arrhenius plot. The extracellular application of phospholipase-A2 or-C suppressed the fusion yield. Thus, it appears that the phospholipid domains play a crucial role in the electric pulse-induced cell fusion. Treatment of the cells with proteolytic enzymes markedly enhanced the fusion yield, presumably due to removing the glycocalix and/or giving rise to fusion-potent, protein-free lipid domains. The presence of millimolar concentrations of divalent cations (irrespective of Mg2+ or Ca2+) as well as of micromolar concentrations of Ca2+ (but not Mg2+) was prerequisite to the resealing of membranes suffered from electrical breakdown upon exposure to electric pulses. In addition, extracellular Ca2+ (but not Mg2+) ions at more than micromolar concentrations were indispensable for the cell fusion.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 86 (1985), S. 9-15 
    ISSN: 1432-1424
    Keywords: molluscan neurone ; patch voltage-clamp technique ; single Cl channel ; calcium ; potassium ; multiplicity of the condutance states
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Properties of the single Cl− channels were studied in excised patches of surface membrane from molluscan neurones using single-channel recording technique. These channels are controlled by Ca2+ and K+ acting on cytoplasmic and outer membrane surfaces, respectively, and by the membrane potential. The channels display about 16 intermediate conductance sublevels, each of them being multiples of ∼12.5 pS. The upper level of the channel conductance is about 200 pS. The channel behavior is consistent with an aggregation of channel-forming subunits into a cluster.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    Springer
    The journal of membrane biology 83 (1985), S. 147-156 
    ISSN: 1432-1424
    Keywords: Exocytosis ; proton pump ; calcium ; secretion ; adrenal medulla
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Calcium-dependent exocytosis in ‘leaky’ bovine adrenal medullary cells has a requirement for Mg-ATP. One possibility is that exocytosis depends in some way on the operation of the ATP-dependent proton pump that serves to maintain the core of the secretory vesicles both acid and at a positive potential with respect to the cytosol. This possibility has been tested in ‘leaky’ cells by monitoring exocytosis under conditions where the secretory vesicle pH and potential gradients are measuredin situ. The results show rather clearly that exocytosis can persist, with unchanged Ca-activation kinetics, in the virtual absence both of a difference in pH between the cytosol and secretory vesicle core and also of a difference in potential across the vesicle membrane. The results do not, however, exclude a small modulating effect of vesicle pH or potential on exocytosis and shed no light on whether or not the plasma membrane potential, which is maintained close to zero in these experiments, influences exocytosis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    ISSN: 1432-1424
    Keywords: sodium/calcium exchange ; excitation-contraction coupling ; sarcolemma ; membrane potential ; sodium ; calcium ; heart
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The effect of membrane potential on sodium-dependent calcium uptake by vesicles in an isolated cardiac sarcolemma preparation was examined. Initial time course studies showed that the reaction deviated from initial velocity conditions within minutes. This appeared to be due, in part, to loss of the sodium gradient. Assays carried out to 10 sec revealed a linear component of uptake (2 to 10 sec) and a faster component (complete by 2 sec). The latter was eliminated by loading the preparation with ethyleneglycol-bis-(β-aminoethyl ether)N,N′-tetraacetic acid (EGTA). This maneuver did not affect the slow component, and subsequent studies used preparations containing EGTA. Potassium Nernst potentials (E K), established by potassium gradients in the presence of valinomycin, were varied from −100 to +30 mV by changing [K+] o from 1.18 to 153.7mM ([K+] i =50mM). The initial velocity of sodium-dependent calcium uptake was stimulated twofold by changingE K from −100 to 0 mV and another twofold by raisingE K from 0 to +30 mV. For the total range ofE K and [K+] o , 32 to 36% of the increase appeared to reflect stimulation by extravesicular potassium. The remainder appeared to be due to membrane potential. The profile of sodium-dependent calcium uptake versusE K suggested that calcium influx through electrogenic sodium/calcium exchange may be much more affected by the positive region of the cardiac action potential than by the negative region.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    ISSN: 1432-1424
    Keywords: calcium ; rod photoreceptors ; surface potentials
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary The nature of the Ca2+ buffer sites in intact rod outer segments isolated from bovine retinas (ROS) was investigated. The predominant Ca2+ buffer in intact ROS was found to be negatively charged groups confined to the surface of the disk membranes. Accordingly, Ca2+ buffering in ROS was strongly influenced by the electrostatic surface potential. The concentration of Ca2+ buffer sites was about 30mm, 80% of which were located at the membrane surface in the intradiskal space. A comparison with observations in model systems suggests that phosphatidylserine is the major Ca2+ buffer site in ROS. Protons and alkali cations could replace Ca2+ as mobile counterions for the fixed negatively charged groups. At physiological ionic strength, the total number of these diffusible, but osmotically inactive, counterions was as large as the number of osmotically active cations in ROS. The surface potential is dependent on the concentration of cations in ROS and can be measured with the optical dye neutral red. Addition of cations to the external solution led to the release of the internally bound dye as the cations crossed the outer membrane. The chemical and spectral properties of the dye enable its use as a real-time indicator of cation transport across the outer envelope of small particles in suspension. In this study, the dye method is illustrated by the use of well-defined ionophores in intact ROS and in liposomes. In the companion paper this method is used to describe the cation permeabilities native to ROS.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    ISSN: 1432-1424
    Keywords: surface charge ; potassium channel ; calcium ; phosphatidylserine ; planar bilayer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary A Ca-activated, K-selective channel from plasma membrane of rat skeletal muscle was studied in artificial lipid bilayers formed from either phosphatidylethanolamine (PE) or phosphatidylserine (PS). In PE, the single-channel conductance exhibited a complex dependence on symmetrical K+ concentration that could not be described by simple Michaelis-Menten saturation. At low K+ concentrations the channel conductance was higher in PS membranes, but approached the same conductance observed in PE above 0.4m KCl. At the same Ca2+ concentration and voltage, the probability of channel opening was significantly greater in PS than PE. The differences in the conduction and gating, observed in the two lipids, can be explained by the negative surface charge of PS compared to the neutral PE membrane. Model calculations of the expected concentrations of K+ and Ca2+ at various distances from a PS membrane surface, using Gouy-Chapman-Stern theory, suggest that the K+-conduction and Ca2+-activation sites sense a similar fraction of the surface potential, equivalent to the local electrostatic potential at a distance of 9 Å from the surface.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of experimental biology and medicine 99 (1985), S. 417-420 
    ISSN: 1573-8221
    Keywords: rat neuromuscular junction ; calcium ; tetanus toxin ; ouabain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    ISSN: 1573-5117
    Keywords: calcium ; bicarbonate ; sulphate ; acidity ; Rhine ; Rhone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Data on the chemical composition of the hard water rivers Rhine and Rhone, published elsewhere, are stored in a new data bank, RRQUE. In this paper the seasonal variation in pH and concentrations of calcium, bicarbonate and sulphate at 7 stations in the Rhine and 7 in the Rhone are described. The concentrations of calcium, bicarbonate and sulphate show important increases with increasing distance from the source. In both rivers acidification gradually occurs downstream and is thought to be caused by the decomposition of disposed organic matter. It is shown that the normal seasonal patterns of these 4 chemical variables are negated by anthropogenic effects.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    ISSN: 1573-5117
    Keywords: pH ; calcium ; bicarbonate ; sulphate ; Rhine ; Rhone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In the hard water rivers Rhine and Rhone the quotient Ca/HCO3 is strongly related to the sulphate concentration and not to the pH. The relationship can be described (by least square analysis) for the Rhine: Ca/HCO3) = 0.70 + 0.5 (SO4), for the Rhone: (Ca/HCO3) = 0.85 + 0.43 (SO4). With a Teissier analysis (reduced major axis) a slope for both rivers of 0.58 has been found. These values equal the theoretically expected value of 0.5, when a solution of CaSO4 is added to a saturated solution of CaCO3. The source of the CaSO4 (gypsum) is thought to be natural in the Rhone and anthropogenic in the Rhine. Acidification of both rivers is probably the result of decomposition of disposed organic matter.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    ISSN: 1573-5117
    Keywords: calcium ; o-phosphate ; apatite ; solubility product ; Rhine ; Rhone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The ionic product of 10750oxy-apatite has been calculated from data sets from the hard water rivers Rhine and Rhone. An overall value of 10−50 has been obtained, but this value has an uncertainty due to the uncertainty of the third ionisation constant of phosphoric acid. Implicitly it has been shown that these rivers are saturated with respect to 10750oxy-apatite and that thus calcium controls the solubility of o-phosphate.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    Springer
    Journal of bioenergetics and biomembranes 17 (1985), S. 183-200 
    ISSN: 1573-6881
    Keywords: (Na + K)-ATPase ; phosphatase ; calcium ; magnesium ; manganese ; oligomycin ; dimethyl sulfoxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Phosphatase activity of a kidney (Na + K)-ATPase preparation was optimally active with Mg2+ plus K+. Mn2+ was less effective and Ca2+ could not substitute for Mg2+. However, adding Ca2+ with Mg2+ or substituting Mn2+ for Mg2+ activated it appreciably in the absence of added K+, and all three divalent cations decreased apparent affinity for K+. Inhibition by Na+ decreased with higher Mg2+ concentrations, when Ca2+ was added, and when Mn2+ was substituted for Mg2+. Dimethyl sulfoxide, which favorsE 2 conformations of the enzyme, increased apparent affinity for K+, whereas oligomycin, which favorsE 1 conformations, decreased it. These observations are interpretable in terms of activation through two classes of cation sites. (i) At divalent cation sites, Mg2+ and Mn2+, favoring (under these conditions)E 2 conformations, are effective, whereas Ca2+, favoringE 1, is not, and monovalent cations complete. (ii) At monovalent cation sites divalent cations compete with K+, and although Ca2+ and Mn2+ are fairly effective, Mg2+ is a poor substitute for K+, while Na+ at these sites favorsE 1 conformations. K+ increases theK m for substrate, but both Ca2+ and Mn2+ decrease it, perhaps by competing with K+. On the other hand, phosphatase activity in the presence of Na+ plus K+ is stimulated by dimethyl sulfoxide, by higher concentrations of Mg2+ and Mn2+, but not by adding Ca2+; this is consistent with stimulation occurring through facilitation of an E1 to E2 transition, perhaps an E1-P to E2-P step like that in the (Na + K)-ATPase reaction sequence. However, oligomycin stimulates phosphatase activity with Mg2+ plus Na+ alone or Mg2+ plus Na+ plus low K+: this effect of oligomycin may reflect acceleration, in the absence of adequate K+, of an alternative E2-P to E1 pathway bypassing the monovalent cation-activated steps in the hydrolytic sequence.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular neurobiology 5 (1985), S. 123-145 
    ISSN: 1573-6830
    Keywords: activity dependence ; adenylate cyclase ; associative learning ; calcium ; classical conditioning ; cyclic AMP ; presynaptic facilitation ; synaptic plasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. In studying the classical conditioning of the siphon withdrawal reflex inAplysia, we have identified a neuronal mechanism that plays an important role in this conditioning: activity-dependent presynaptic facilitation. This review describes our analysis of the cellular basis of this associative mechanism. During the conditioning of the withdrawal reflex, the unconditioned stimulus, a tail shock, produces presynaptic facilitation of synaptic transmission from the siphon sensory neurons in the conditioned stimulus pathway. The facilitation is enhanced if a sensory neuron has fired action potentials just prior to receiving facilitatory input, as occurs during training when the conditioned stimulus precedes the unconditioned stimulus. This activity-dependent enhancement of presynaptic facilitation provides a mechanism for the temporal specificity in conditioning of the reflex. 2. Activity-dependent facilitation appears to involve the same cyclic AMP (cAMP)-dependent cascade that underlies presynaptic facilitation in these neurons in the absence of paired spike activity. Our evidence suggests that it is the transient elevation of intracellular Ca2+ that is responsible for the enhancement of the facilitation response by paired spike activity. Moreover, our preliminary results indicate that Ca2+/calmodulin is able to potentiate the activation of adenylate cyclase inAplysia neurons by facilitatory transmitter. Thus, the dual activation of the calmodulin-dependent cyclase by Ca2+ and transmitter may give this enzyme an important associative role in learning. In the conclusion, the possible phylogenetic generality of this associative mechanism is discussed as well as its possible role in activity-dependent processes in neuronal development.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 11 (1985), S. 11-20 
    ISSN: 1573-1561
    Keywords: European elm bark beetle ; Scolytus multistriatus ; Coleoptera ; Scolytidae ; control ; chlorpyrifos ; cacodylic acid ; trapping ; trap tree ; Dutch elm disease ; multilure ; attraction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract European elm bark beetles,Scolytus multistriatus (Marsh.), were strongly attracted to American elms,Ulmus americana L., baited with theS. multistriatus attractant, multilure, or killed by injection of the arboricide, cacodylic acid; a combination of the two treatments was most attractive. Comparisons of beetle catches on sticky bands affixed to the trees with samples of bark from the same trees showed that the number of beetles landing on cacodylic acid-treated trees was approximately 40 times greater than the number boring into them. Spraying the bark with the insecticide chlorpyrifos had no direct effect on attraction. No live bark beetle brood was found in trees that had been treated with cacodylic acid or chlorpyrifos, but trees that were only baited or left untreated (check) were attacked, killed, and colonized. We suggest that the contribution of the cacodylic acid trap tree technique to Dutch elm disease control will be enhanced by baiting treated trees with multilure and spraying their lower boles with 0.5% chlorpyrifos. This treatment will eliminate diseased and unwanted elms as potential breeding material and kill large numbers of elm bark beetles that might otherwise innoculate healthy elms with the Dutch elm disease fungus.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 11 (1985), S. 311-318 
    ISSN: 1573-1561
    Keywords: cucurbitacins ; defense compounds ; Diabrotica spp. ; Acalymma vittatum ; insect/plant interaction ; Tenodera aridifolia sinensis ; Coleoptera ; Chrysomelidae ; Orthoptera ; Mantidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Four species of diabroticites with different host specificities are shown for the first time to sequester cucurbitacins. While all beetles fed on an artificial diet (no cucurbitacins) were readily consumed by Chinese praying mantids, a significant proportion of adultDiabrotica balteata (72%),D. undecimpunctata howardi (46%), andD. virgifera virgifera (24%) fed on squash fruit containing cucurbitacins B and D were rejected. Moreover, even when adults did not feed on cucurbitacins, 21–24% ofAcalymma vittatum were rejected by the mantids which is consistent with larval sequestration of cucurbitacins. The mantids failed to learn to avoid any of the beetle species despite adverse effects associated with ingestion, i.e., uncoordination, regurgitation, etc. A cucurbitacin D metabolite accumulated and was sequestered for extended periods of time in the hemolymph of all four species. In addition, female beetles that had ingested cucurbitacins laid eggs containing substantial amounts of cucurbitacins.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 11 (1985), S. 1083-1092 
    ISSN: 1573-1561
    Keywords: Chemical defense ; Zophobas atratus ; Coleoptera ; Tenebrionidae ; defensive secretion ; gland recharge ; defensive quinone ; quinone production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Beetles were milked of their abdominal defensive secretion at three different frequencies over the first 36 days of adult life. Secretion production decreased greatly with age from a maximum of 94 nmol/day at 4–6 days to a basal level of about 25 nmol/day at 30–40 days. Ethyl- and methylquinone comprised the bulk of the secretion and were most strongly affected by age. Benzoquinone was most strongly affected by milking frequency. An average adult produced an estimated 4445 nmol of total secretion in its 5-month life-span but had reservoirs large enough to store 11,000 nmol. Males produced more secretion than females because of their larger size and inherent sexual differences. As they aged, mated females showed a more rapid decrease in production that virgin females. The defensive system appears to be programed to charge glands rapidly with secretion early in adult life and fall of to a low recharge rate little affected by discharge.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 11 (1985), S. 73-83 
    ISSN: 1573-1561
    Keywords: Colorado potato beetle ; Leptinotarsa decemlineata ; Coleoptera ; Chrysomelidae ; feeding deterrents ; Solanaceae ; Solanum alkaloids ; chemo-receptors ; mouthpart sensilla ; tomatine ; solanine ; chaconine ; demissine ; leptine III
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Steroidal glycoalkaloids, found in species of the Solanaceae, elicit bursting activity in galeal and tarsal chemosensilla of adult Colorado potato beetles. The effect has an average latency of 6–12 sec, depending on the sensillum/alkaloid combination. A 20-sec alkaloid treatment is often suffficient to render galeal sensilla unresponsive to gamma-aminobutyric acid, normally an effective stimulant. The alkaloids have similar effects on galeal sensilla of larval Colorado potato beetles and on labellar chemosensilla of the blowfly. It is concluded that these compounds act independently of any specialized chemoreceptor in the Colorado potato beetle, and that association of the Colorado potato beetle with solanaceous plants has not led to evolution of a specific receptor forSolanum glycoalkaloids.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 11 (1985), S. 1371-1387 
    ISSN: 1573-1561
    Keywords: Asymmetric synthesis ; stereoisomers ; sex pheromone ; Diabrotica ; Coleoptera ; Chrysomelidae ; (R)-2-methylbutyric acid ; HPLC ; diastereomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Details of the syntheses of the four stereoisomers of 8-methyl-2-decanol and its propanoate ester are given. The racemic ester, two of its stereoisomers, and one stereoisomer as an acetate are attractive to several species ofDiabrotica. The key steps in the syntheses involve high-performance liquid chromatograpic resolutions of diastereomers to achieve high configurational enrichment of each site and generation of (R)-2-methylbutyric acid by chemical degradation ofd-isoleucine.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    ISSN: 1573-1561
    Keywords: Benzoquinones ; defensive secretion ; 2-heptadecanone ; hepta-dec-10-en-2-one ; heptadecene ; 2-methoxyphenol ; nonadec-lO-en-2-one ; 2-pentadecanone ; pentadecene ; 2-pentanone ; Uloma tenebrionoides ; Coleoptera ; Tenebrionidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The defensive secretion ofUloma tenebrionoides (White, 1846) contains benzoquinone, 2-methylbenzoquinone (toluquinone), and 2-ethylben-zoquinone as in other tenebrionids, together with 2-methoxyphenol, pentadecene, heptadecene, 2-pentanone, 2-pentadecanone, 2-heptadecanone, heptadec-10-en-2-one and (Z)-nonadec-10-en-2-one. The latter four methyl ketones have not previously been identified in tenebrionid beetles, and the unsaturated ketones are novel arthropod chemicals.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 11 (1985), S. 1553-1565 
    ISSN: 1573-1561
    Keywords: Herbivory ; chemical quantitative variation ; specialist herbivore ; parasitism ; growth reduction ; Encelia farinosa ; Asteraceae ; Trirhabda geminata ; Coleoptera ; Chrysomelidae ; Chaetonodexodes vanderwulpi ; Diptera ; Tachinidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Larvae of the monophagous herbivore,Trirhabda geminata, selectively eat particular plants and plant parts of its natural host,Encelia farinosa. Measurements of leaf damage and larval positions on branches through time support this observation. Time-lapse movie photography revealed that larvae are sufficiently mobile to search most of a plant in a 48-hr period and that aggregations were the result of larval activity and not directly the result of oviposition. Experiments withT. geminata larvae on artificial diets containing a range of natural concentrations of chemical extracts fromE. farinosa leaves showed that the larvae grew significantly slower and had a lower overall survivorship at the high concentration. Combining the results of all choice tests, larvae appeared unable to distinguish between high- and low-concentration agar diets. Considered individually, larval preferences for natural production concentrations changed as the season progressed. Early-season larvae preferred low-concentration leaves, while late-season larvae preferred high-concentrations. Measurements of chemical and nitrogen content of leaves selected by larvae in the field confirmed this pattern. Percent parasitism in field-collected larvae increased with season as the larval population decreased. This combination of slowed growth and increasing parasitism and predation is a putative defense strategy ofEncelia farinosa to prevent adaptation by a specialist herbivore to the total range of compounds elaborated.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 11 (1985), S. 539-544 
    ISSN: 1573-1561
    Keywords: Ammonia utilization ; l-canavanine catabolism ; Caryedes brasiliensis ; Coleoptera ; Bruchidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The seed predator,Caryedes brasiliensis [Bruchidae] generates appreciable ammonia in its dietary use and detoxification ofl-canavanine and its catabolic product,l-canaline.l-Canavanine is a toxic allelochemical ofDioclea megacarpa seeds, the food of the developing larvae. Bruchid beetle larvae rely upon glutamic acid dehydrogenase and glutamine synthetase to use ammonia for glutamic acid synthesis from 2-oxoglutaric acid and conversion of the former to glutamine. These reactions provide the larvae with a means for metabolically eliminating ammonia. Proline serves as a carbon skeleton source for glutamic acid formation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    ISSN: 1573-1561
    Keywords: Oryzaephilus surinamensis ; saw-toothed grain beetle ; Coleoptera ; Silvanidae ; attractant ; carobs ; Ceratonia siliqua ; volatiles ; vacuum distillation ; hexanoic (caproic) acid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Vacuum distillation of heat-treated carobs gave an aqueous, colorless, sweet-smelling distillate which was tested over a wide range of concentrations and found to be highly attractive to adultOryzaephilus surinamensis (L.). The materials responsible for the aroma were isolated from the distillate by saturating with sodium chloride and extracting into diethyl ether as separate acidic, neutral, and basic fractions. The extraction efficiency was checked by recombining portions of the three fractions and replacing the diethyl ether with water to give a “reconstituted distillate;” this was almost as attractive as the original distillate. Bioassay of aqueous solutions of the three separate fractions showed that the acidic was attractive, while the neutral and basic had little effect. The five major components of the acidic fraction were found to be acetic, isobutyric,n-butyric, 2-methylbutyric, and hexanoic (caproic) acids. Bioassay of these in aqueous solution, both separately and combined, showed that hexanoic acid was the most attractive and may be responsible for both the longer-lasting attractive effect of the carob distillate and for the effectiveness of carobs themselves used in bait bags to detect stored product insects.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 11 (1985), S. 767-779 
    ISSN: 1573-1561
    Keywords: Host plant ; biological control of weeds ; Trirhabda bacharides ; Coleoptera ; Chrysomelidae ; Compositae ; Baccharis ; green leaf volatiles ; plant odor ; electroantennogram ; olfaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Electroantennograms (EAGs) were recorded fromTrirhabda bacharides Le Conte (Coleoptera: Chrysomelidae) females to 28 odorants and volatiles emanating from leaves of 26 plant species including three known host plants,Baccharis halimifolia L.,B. neglecta Britt, andB. salicina T. & G. (Compositae: Asterae). Antennal receptors were highly responsive to components of the green leaf volatile complex, especially 6-carbon saturated and monounsaturated alcohols andtrans-2-hexenal. EAGs elicited by heptanal were greater than those elicited by any other saturated aldehyde. Oxygenated monoterpenes were more active than monoterpene hydrocarbons. β-Bisabolol was the most active sesquiterpene. In general, EAGs to volatiles emanating fromBaccharis and other composite species were greater than those elicited by species from other families. Furthermore, when one considers only plants occurring in the environs ofT bacharides hostB. neglecta, EAGs elicited by its host plant were at least two times greater than those elicited by other coinhabiting plants.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 11 (1985), S. 999-1007 
    ISSN: 1573-1561
    Keywords: Pine engraver beetle ; Ips pini ; Coleoptera ; Scolytidae ; (+)-ipsdienol ; (−)-ipsdienol ; pheromone receptor ; response specificity ; electrophysiology ; interpopulational hybrid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Electrophysiological studies of pheromone receptor cells keyed to ispdienol were performed in laboratory-raised hybrids of the eastern and western populations of the pine engraver,Ips pini. As previously shown in the parental beetles, the receptor cells keyed to ipsdienol could be classified as two distinct types: one keyed to (+)- and one to (−)-ipsdienol. None of the 20 ipsdienol cells recorded from F1 hybrids were of an intermediate type. Recordings of the summated receptor responses (EAGs) showed no significant difference between parental beetles and hybrids. Similar results were obtained in reciprocal crosses, eastern females with western males and the reverse. Thus, there was no indication that sex-linked alleles determined the specificity of the ipsdienol receptor cell. The ratio between (+) and (−) cells was 14∶6 in the hybrids compared to 1∶12 in the western and 9∶12 in the eastern populations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 11 (1985), S. 1249-1261 
    ISSN: 1573-1561
    Keywords: Pinus ponderosa ; Dendroctonus brevicomis ; pheromone ; attractant ; interruptant ; exo-brevicomin ; frontalin ; Coleoptera ; Scolytidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract After living ponderosa pines were baited with either female-infested bolts or synthetic pheromones,Dendroctonus brevicomis were caught on sticky screens throughout trapping periods of 15–46 days; however, large numbers of beetles were trapped during only a small portion (5–10 days) of these trapping periods. The most attractive portions of trees attacked contained 3–6 beetles dm2, in galleries ca. 2 cm long. Catch increased following addition of males to female-infested bolts, supporting the hypothesis that male-produced frontalin is an attractive pheromone of the western pine beetle. Catch at bolts removed from trees under attack was strongly dependent upon levels of boring activity. We found no evidence of interruption of the response to attractants during host colonization.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    ISSN: 1573-1561
    Keywords: Sex pheromone ; Lasioderma serricorne F. ; cigarette beetle ; Coleoptera ; Anobiidae ; serricornin ; polyketide biosynthesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A chemical study of the sex pheromone of the cigarette beetle was carried out. Seven components were isolated from active fractions of column chromatography of the female extract, and their structures were elucidated by spectroscopic evidence and confirmed by synthesis to be (4S,6S,7S)-4,6-di-methyl-7-hydroxynonan-3-one (serricornin) (I), 2,6-diethyl-3,5-dimethyl-3,4-dihydro-2H-pyran (anhydroserricornin) (II), 4,6-dimethylnonan-3,7-dione (III), 4,6-dimethylnonan-3,7-diol (IV), 4,6-dimethyl-7-hydroxy-4-nonen-3-one (V), (2S,3R)-2,3-dihydro-3,5-dimethyl-2-ethyl-6-(l-methyl-2-oxobutyl)-4H-pyran-4-one (serricorone) (VI) and (2S,3R)-2,3-dihydro-3,5-dimethyl-2-ethyl-6-(1-methyl-2-hydroxybutyl)-4H-pyran-4-one (serricorole) (VII). These structural features suggested that the occurrence of these components might be related to the polyketide biosynthesis. The behavioral bioassay and BAG experiments revealed the biological role of each component in the copulatory behavior of this insect.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    ISSN: 1573-1561
    Keywords: Electroantennogram ; grape borer ; Xylotrechus pyrrhoderus ; Bates ; Coleoptera ; Cerambycidae ; male sex pheromone ; (2S,3S)-octanediol ; (2S)-hydroxy-3-octanone ; optical isomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Electroantennograms were recorded from the grape borerXylotrechus pyrrhoderus in response to serial dilutions of male sex pheromone components, (2S,3S)-octanediol and (2S)-hydroxy-3-octanone, and to 100 μg of their optical isomers and host plant substances. Female antennae always responded more strongly than male antennae. Antennae of both sexes were highly sensitive to (2S)-hydroxy-3-octanone. F/M ratio (female to male EAG value) was greater for male sex pheromone components, especially (2S,3S)-octanediol, and their optical isomers than plant substances. Antennal sensitivity to optical isomers (2R,3R-octanediol and 2S,3R-octanediol) was lower than true pheromone components.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    ISSN: 1573-1561
    Keywords: Coleoptera ; Staphylinidae ; Deleaster dichrous ; defensive secretion ; gland system ; iridodial adhesive ; isopropyl esters ; sec-butyl esters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The phylogenetically primitive rove beetleDeleaster dichrous (Grav.) (Oxytelinae) has been shown for the first time to possess two pairs of neighboring abdominal glands which are depleted simultaneously on molestation. The morphology of these glands is described. The defensive constituents of theDeleaster glands were elucidated directly from the mixtures by gas chromatographic-mass spectroscopic methods and microchemical reactions. The paired whitish glands secrete iridodial, which polymerizes on exposure to air to form an adhesive that probably deters small predatory arthropods. The red gland system ofD. dichrous contains the toxicp-toluquinone and a variety of isopropyl andsec-butyl esters. Artificial quinoid ester mixtures simulating the secretion ofD. dichrous showed only weak effects on mortality ofLucilia larvae in comparison with more effective secretions of phyiogenetically derived Oxytelinae. The secretion of the primitive genusDeleaster is characterized chemotaxonomically by β, γ-unsaturated C12 acids and esters, which are postulated as precursors for the characteristic defensive compounds of the derived species, thus indicating a clear evolutionary trend at the micromolecular level.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    ISSN: 1573-1561
    Keywords: Cryptolestes turcicus ; Coleoptera ; Cucujidae ; aggregation pheromone ; macrolide ; (Z,Z)-5,8-tetradecadien-13-olide ; (Z)-5-tetradecen-13-olide ; enantiomeric synergism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Two biologically active macrolides were isolated from Porapak Q-captured beetle and frass volatiles ofCryptolestes turcicus (Grouvelle) and identified spectroscopically as (Z,Z)-5,8-tetradecadien-13-olide (I) and (Z)-5-tetradecen-13-olide (II). Natural I was active alone and was synergized by inactive II. The pheromones were male-produced but attractive to both sexes. Pheromone production increased dramatically when insects were aerated on a food source. Pure (R)- and (S)-I were inactive, but mixtures of (R)- and (S)-I were active, the first reported instance of enantiomeric synergism in the Cucujidae.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    ISSN: 1573-0603
    Keywords: fluorescence polarization ; membrane fluidity ; rat hepatocytes ; cadmium ; calcium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Steady-state fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) incorporated into plasma membranes of parenchymal hepatocytes provides a simple method of monitoring the immediate interactions of divalent cations with these membranes. Excitation of the fluorescent probe with vertically polarized light and monitoring of the vertical and horizontal components of the emitted light during the excited state lifetime of the probe provides a measure of DPH rotation. Membrane fluidity is evaluated on the basis of rotation of the fluorescent probe. Direct measurements of intermolecular events within plasma membranes are obtained after perturbation by individual metals and metalloids or combinations thereof. This technique has been useful in monitoring the effects of increasing concentrations of calcium or of increasing concentrations of cadmium in the presence or absence of calcium. Interactions of plasma membranes with such divalent metal cations, as well as other toxic substances, probably represents the first step in the series of cytotoxic reactions manifested by parenchymal hepatocytes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular neurobiology 5 (1985), S. 47-63 
    ISSN: 1573-6830
    Keywords: dendritic spines ; synaptic plasticity ; spine apparatus ; calcium ; actin filaments ; spine apparatus as a calcium-sequestering organelle ; contractile proteins may underlie synaptic plasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary 1. A number of experimental procedures which induce increased electrical activity (including long-term potentiation) were shown to be accompanied by morphometric changes in dendritic spines. These changes include an enlargement of the spine head, shortening and widening of the spine stalk, and an increase in the length of synaptic apposition. 2. A possible mechanism is suggested which takes into account specific cytological features of the spine and the existence of contractile proteins in neurons. Dendritic spines are defined as special domains of the neuron which have a unique organization of the cytoplasm. Actin filaments form a very dense network in the spine head, and they are longitudinally organized within the spine stalk. Spines were also shown to contain myosin and other actin-regulatory proteins. The high density of the actin network could explain the characteristic absence of the cytoplasmic organelles from dendritic spines. 3. In analogy with other cells, such an actin organization indicates low levels of free cytosolic calcium. Even in the resting state, calcium levels may be unevenly distributed through the neuron, being lowest within the subplasmalemmal region. Due to the high surface-to-volume ratio in spines, the cytoplasm is formed mostly by the subplasmalemmal region. The spine apparatus or the smooth endoplasmic reticulum, which is recognized as a calcium-sequestering site in spines, may also contribute to the low calcium levels there. 4. However, when in the stimulated spine the voltage-dependent calcium channels open, then, given the spine's high surface-to-volume ratio, the concentration of calcium may very quickly attain levels that will activate the actin-regulatory proteins and myosin and thus trigger the chain of events leading to the enlargement of the spine head and to the contraction (i.e., widening and shortening) of the spine stalk. The increased free cytosolic calcium may also activate the protein-producing system localized at the base of the spine, which, under certain conditions, could stabilize the morphometric changes of the spine.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    ISSN: 1573-1561
    Keywords: Olfaction ; receptor cell ; chirality ; perception ; neurobiology ; pheromone ; enantiomer ; bark beetle ; electrophysiology ; Douglas-fir beetle ; Dendroctonus pseudotsugae ; Coleoptera ; Scolytidae ; (+)-frontalin ; (−)-frontalin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Olfactory perception of pheromonal enantiomers by male and female Douglas-fir beetles,Dendroctonus pseudotsugae Hopk. (Coleoptera: Scolytidae), was investigated by electrophysiological techniques and behavioral bioassays. Electroantennograms (EAGs) and single-cell responses indicated both sexes to be more responsive to racemic frontalin and the (−)-enantiomer at lower dosages. At higher dosages, little difference was noted in responses to either enantiomer. However, response to the racemic mixture at higher dosages was slightly greater than responses to either enantiomer alone. In laboratory behavioral bioassays, responses to low concentrations of (−)-frontalin and the racemic mixture exceeded response to the (+)-enantiomer alone. At a higher concentration, responses to the racemic mixture or either enantiomer alone did not differ. The results indicate that separate enantiomer-specific acceptors may exist on the same pheromone receptor cell.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    ISSN: 1573-1561
    Keywords: Tribolium castaneum ; Coleoptera ; Tenebrionidae ; red flour beetle ; olfactory behavior ; ethyl 9,12-octadecadienoate ; methyl octadecanoate ; methyl tetradecanoate ; methyl pentadecanoate ; ethyl tetradecanoate ; ethyl pentadecanoate ; ethyl octadecanoate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The olfactory responses of red flour beetles,Tribolium castaneum (Herbst), to methyl and ethyl ester of C14–C18 fatty acid prepared from tallow were studied. Methyl octadecanoate and ethyl octadecanoate discouraged aggregation of beetle adults. Ethyl 9.12-octadecadienoate acted as a repellent. Methyl pentadecanoate and ethyl tetradecanoate induced copulation at the level of 5 × 102 and 2 × 103 μg, respectively. The maximum response was observed at the level of 5 × 102 μg of the same compounds, and these compounds appear to stimulate males only.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    ISSN: 1573-1561
    Keywords: Boll weevil ; Anthonomus grandis ; Coleoptera ; Curculionidae ; feeding stimulants ; cotton buds ; anthers ; phytol ; geranylgeraniol esters ; phytol oleate ; phytol dodecanoate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Column chromatography of the pentane extract of freeze-dried cotton buds or anthers yielded a wax-sterol ester fraction that exhibited potent feeding stimulant activity for the cotton boll weevil. The waxes of the wax-sterol ester mixture were responsible for the feeding activity. Saponification of the wax-sterol ester fraction yielded about 15% alcohols and 85% sterols. A C18∶1 alcohol, dihydrophytol, phytol, and geranylgeraniol constituted 15, 36, 26, and 23%, respectively, of the total alcohols, implicating certain of their long-chain esters as feeding stimulants. Several esters of dihydrophytol, phytol, and geranylgeraniol were identified among the waxes by GC-MS. Certain phytol, geranylgeraniol, and oleyl alcohol esters containing C12 to C26 acid moieties were synthesized and were found to induce high feeding stimulant activity in the cotton boll weevil.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    ISSN: 1573-1561
    Keywords: Aggregation pheromone ; attractant ; (R * S *)-5-hydroxy-4-methyl-3-heptanone ; (R * R *)-5-hydroxy-4-methyl-3-heptanone ; sitophilure ; Sitophilus oryzae ; S. zeamais ; S. granarius ; Coleoptera ; Curculionidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A male-produced aggregation pheromone, common to the rice weevil,Sitophilus oryzae, and the maize weevil,S. zeamais, was isolated and identified from hexane extracts of highly absorbent paper disks exposed individually to young virgin male weevils. A combination of preparative column and gas-liquid chromatography of disk extracts yielded purified natural pheromone. When analyzed by nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry, the structure of the natural pheromone, “sitophilure,” proved to be (R *,S *)-5-hydroxy-4-methyl-3-heptanone, of unknown enantiomeric composition. Synthetic racemic pheromone was highly attractive to males and females of both rice and maize weevils. In addition, both sexes of the granary weevil,S. granarius (L.) were attracted to the racemic preparation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 11 (1985), S. 1307-1321 
    ISSN: 1573-1561
    Keywords: Cucurbitacins ; Diabrotica spp. ; Acalymma vittatum ; Coleoptera ; Chrysomelidae ; kairomone metabolism ; detoxification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Five species of diabroticites with different host-plant preferences produced an essentially identical array of metabolites when fed radiolabeled cucurbitacin B synthesized in vivo and purified fromCucurbita maxima Duchesne seedlings. All species excreted the bulk of the cucurbitacin (67,17-94.59% total dpm), permanently sequestered a small proportion of a cucurbitacin conjugate in the hemolymph (0.98–2.76%), and apportioned the remainder between the gut, the body, and the eggs (when present). Markedly different ratios between the excretory metabolites (i.e., polar vs. unmetabolized cuc) suggest thatDibrotica virgifera virgifera, a grass specialist, andAcalymma vittatum, a cucurbit specialist, have lower rates of metabolic alteration than the polyphagousD. undecimpunctata howardi, D. balteata, andD. cristata, which is associated with relict prairies. Mean life-spans ofD. balteata and D. v. virgifera and maleA. vittatum decreased significantly with continuous feeding onCucurbita fruit containing cucurbitacins (vs. fruit devoid of cucs). The longevity of femaleA. vittatum, however, was unaffected by the presence of cucurbitacins.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    Springer
    Bulletin of experimental biology and medicine 99 (1985), S. 317-320 
    ISSN: 1573-8221
    Keywords: strophanthin G ; calcium ; contractile function of heart muscle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...