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
  • Gas chromatography  (39)
  • Escherichia coli  (33)
  • Hymenoptera  (33)
  • Springer  (105)
  • Cell Press
  • 2005-2009
  • 1985-1989  (105)
  • 1980-1984
  • 1988  (105)
Collection
Keywords
Years
  • 2005-2009
  • 1985-1989  (105)
  • 1980-1984
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of industrial microbiology and biotechnology 3 (1988), S. 21-28 
    ISSN: 1476-5535
    Keywords: Diaper ; Staphylococcus aureus ; Escherichia coli ; Candida albicans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Methods were developed to study the effects of absorbent materials from diapers on microbial survival, growth and toxic shock syndrome toxin-1 (TSST-1) production under specified in vitro conditions. Growth of representative skin and fecal flora organisms was equivalent in cultures in which materials from cotton cloth diapers, disposable diapers or disposable diapers containing absorbent gelling material were added as the sole carbon source. In urine used as an enrichment medium, growth of the test organisms in media containing material from the three diaper types was equivalent and no contribution to growth from the diaper material was detected. TSST-1 was not produced byStaphylococcus aureus under conditions in which urine was added to the diaper materials. Pathogenic strains of organisms purposefully introduced onto diapers failed to survive and the few microbial cells normally found in diaper material did not multiply when stored under conditions favorable to microbial growth. The data indicate that all three diaper types tested were the same with respect to growth and survival of representative skin and fecal organisms.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of insect behavior 1 (1988), S. 379-386 
    ISSN: 1572-8889
    Keywords: cannibalism ; caste ; development ; Mischocyttarus ; Hymenoptera ; larva ; nourishment ; saliva ; trophallaxis ; Vespidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Journal of insect behavior 1 (1988), S. 387-392 
    ISSN: 1572-8889
    Keywords: Leptopilina heterotoma ; Hymenoptera ; parasitoid ; foraging ; microhabitat preference ; learning ; experience
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Cellular and molecular life sciences 44 (1988), S. 848-853 
    ISSN: 1420-9071
    Keywords: DNA probes ; cytotoxin and enterotoxin genes ; Escherichia coli ; Shigella spp
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary DNA probes to identify the genes encoding toxins in enteric bacteria have been developed. Use of these probes reduces the number of animals required for toxicity testing, as suspect bacteria can be directly tested for the presence of toxin. We have augmented the gene probes available by developing probes against theEscherichia coli enterotoxin LTII and shiga toxin fromShigella dysenteriae 1. The LTII gene fromE. coli 357900 was identified and characterised and a suitable internal probe was obtained. The LTII gene was found not to be common among enterobacteriae from various geographical locations. Isolates predominately of animal origin from Nigeria and Thailand hybridized with the probe. The shiga toxin gene was isolated fromS. dysenteriae 1 by a combination of in vivo and in vitro methods. An internal probe was identified and used against different serogroups ofShigella andE. coli isolated. The probe was found to hybridize withS. dysenteriae 1 isolates and also someS. flexneri andS. sonnei strains. Representatives were tested for toxin production and found to produce toxin at low levels.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1570-7458
    Keywords: Hymenoptera ; Encyrtidae ; parasitoids ; Pseudococcidae ; mealybugs ; Anagyrus pseudococci ; Leptomastix dactylopii ; Leptomastidea abnormis ; temperature ; predicting development ; thresholds ; temperate glasshouses
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les vitesses de développement de 3 parasitoïdes de cochenilles ont été étudiées dans les conditions de température de serre, avec thermopériode ou en température constante. En conditions constantes, la vitesse augmente jusqu'à 35°C, mais est létale à 40°C. Avec thermopériode, une thermophase de 40°C peut être tolérée pendant 12 heures. Les vitesses de développement sous thermopériodes pourraient être calculées à partir des données obtenues en conditions constantes, modifiées en fonction des durées respectives des cryophases et thermophases. Une méthode originale est présentée pour obtenir les seuils inférieurs de développement, en utilisant des thermopériodes, et pour calculer les vitesses de développement à températures élevées. Une méthode de régression polynomiale, non vérifiée préalablement, a été utilisée pour prévoir les durées moyennes des développements sous serre. Ces estimations sont beaucoup plus sûres que les prédictions basées sur le concept de degré-jour (Do), lorsque les températures extrêmes durent longtemps, mais en serre chaude elles ne présentent aucune différence significative. De plus, une méthode d'évaluation des 95% d'émergences, a donné de bonnes estimations des premières et dermières émergences en conditions périodiques.
    Notes: Abstract Developmental rates of three encyrtid mealybug parasitoids were examined under constant, cycling and glasshouse temperatures. Under constant conditions the rate of development increased with rising temperature up to 35°C, but a constant 40°C was lethal. Under cycling conditions, 12 h periods at 40°C could be tolerated. Developmental rates under cycling conditions could be calculated from constant temperature data, by incrementing development on an h/h basis. A new technique was developed to determine the lower thresholds for development, using cycling regimes and to calculate the rates of development over short periods at high temperature. A previously untested polynomial regression technique was used to predict mean developmental periods under glasshouse conditions. These predictions were considerably more accurate than day-degree (Do) predictions when substantial periods at extreme temperatures were involved, but not significantly different from day-degree predictions under ‘hot-house’ conditions. In addition a method was developed to calculate a 95% range for emergence, which gave consistently good estimates of first and last eclosion observed under fluctuating conditions.
    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 46 (1988), S. 117-123 
    ISSN: 1570-7458
    Keywords: trap hosts ; parasitoid ; parasitism ; attack rates ; mealybug ; Hymenoptera ; Encyrtidae ; Epidinocarsis diversicornis ; Acerophagus coccois ; Homoptera ; Pseudococcidae ; Phenacoccus herreni ; cassava ; yuca
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Pendant des expositions de 4 jours dans la nature de plants en pots de M. esculenta contaminés artificiellement par des P. herreni du troisième stade, les densités de cochenilles ont été réduites de 73%: de 235.7–1100.2/par plant contaminé à 63.7–314.2/par plant, par suite des évasions, de la pluie et de la prédation. Les attaques de parasitoïdes ne changent pas suivant les densités de cochenilles. Les mêmes espèces de parasitoïdes, ont été élevées dans à peu près les mêmes proportions (Acerophagus coccois, 88.1%, et Epidinocaris diversicornis, 11.3%) à partir de cochenilles sur pots artificiellement contaminés ou de manioc de la nature. Les taux d'attaques par les parasitoïdes sur les cochenilles artificiellement exposées, associés à un modèle de simulation du parasitisme, ont permis de prévoir avec précision les niveaux de parasitisme observés pour chaque stade dans la population de la nature.
    Notes: Abstract During 4-day field exposure intervals, Phenacoccus herreni Cox & Williams, third-instar mealybugs on artificially infested potted cassava plants were reduced 73% from initial densities of 235.7–1100.2/infested plant to 63.7–314.2/plant due to dispersal, rain, and predation. Frequency of parasitoid attack did not differ between high and low mealybug densities. The same species of parasitoids, in approximately the same proportions, were reared from mealybugs on artificially infested potted plants as from field mealybugs (Acerophagus coccois) Smith, 88.1% and Epidinocarsis diversicornis (Howard), 11.3%. Parasitoid attack rates on artificially exposed mealybugs, when combined with a simulation model of parasitism, accurately predicted observed levels of stage-specific parasitism in the field population.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 46 (1988), S. 173-180 
    ISSN: 1570-7458
    Keywords: Edovum puttleri ; Eulophidae ; Hymenoptera ; Leptinotarsa decemlineata ; host habitat conditioning ; parasitism ; host preference ; biological control
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé L'oophage, E. puttleri a été élevé à partir des oeufs de Leptinotarsa decemlineata et L. texana. Il a été mis en expérience sur l'une des 3 plantes consommées par L. decemlineata: Solanum tuberosum tuberosum, S. melongena et Lycopersicon esculentum. Des expériences de choix ont permis de déterminer ses préférences pour les différentes catégories d'oeufs. Le choix de l'oophage est influencé par l'espèce de Leptinotarsa sur laquelle il a été élevé. E. puttleri élevé sur oeufs de L. decemlineata récoltés sur un mélange des 3 solanées, et mis en présence d'un choix de groupes d'oeufs provenant de ces 3 plantes, a parasité préférentiellement les oeufs récoltés sur S. t. tuberosum; élevé à partir d'oeufs de L. texana récoltés sur S. elaeagnifolium, et mis en présence d'un mélange de pontes des 3 solanées, il a préféré parasiter les oeufs provenant de L. esculentum. Son choix a été influencé aussi par la plante qui l'avait conditionné. E. puttleri, élevé à partir de L. texana et mis en expérience sur des pontes provenant de S. t. tuberosum a préféré pondre sur les oeufs provenant de cette solanée. De même, élevé à partir d'oeufs de L. decemlineata pondus sur S. t. tuberosum, il a préféré pondre sur les oeufs provenant de cette plante. Cependant, les oophages élevés à partir d'oeufs de L. decemlineata provenant de L. esculentum, et mis en présence de pontes provenant de L. esculentum, n'ont pas préféré significativement ces oeufs au détriment de ceux provenant des autres solanées, bien que les pontes récoltées sur L. esculentum aient été parasitées plus fréquemment quand 2 des 3 pontes (une de chaque plante) avaient été sondées ou parasitées. Le parasitisme à l'intérieur d'une ponte (nombre d'oeufs de la ponte parasités, sondés, etc) ne varie pas significativement avec la solanée d'origine. La discussion a porté sur les conséquences de ces observations sur l'écologie de l'oophage et sur la lutte biologique contre L. decemlineata.
    Notes: Abstract The egg parasitoid, Edovum puttleri Grissell, was cultured from eggs of two Leptinotarsa hosts, L. decemlineata (Say) and L. texana Schaeffer, and experienced on eggs from three L. decemlineata food plants, namely potato, Solanum tuberosum tuberosum L., eggplant, S. melongena L., and tomato, Lycopersicon esculentum Mill. Host preference of the various cultures was determined using choice tests. parasitoid choices were influenced by the Leptinotarsa rearing host. Wasps, reared from L. decemlineata eggs from a mixture of all three food plants and experienced on egg masses from all three food plants, preferred to parasitize egg masses from potato. Wasps, reared from L. texana eggs from silver leaf nightshade, S. elaeagnifolium L., and experienced on egg masses from all three food plants, preferred to parasitize egg masses from tomato. Choices were also influenced by the herbivore's food plant that wasps were conditioned to. Wasps, reared from L. texana and experienced on egg masses from potato, preferred to parasitize egg masses from potato. Wasps, reared from L. decemlineata on potato and experienced on egg masses from potato, preferred to parasitize egg masses from potato. Wasps, reared from L. decemlineata on tomato and experienced on egg masses from tomato, did not display a distinct host preference. Within-egg mass parasitism (i.e., number of eggs per mass that were parasitized, probed, etc.) did not consistently differ among the three food plants. The implications of these data in parasitoid ecology and biological control programs for L. decemlineata are discussed.
    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 48 (1988), S. 293-300 
    ISSN: 1570-7458
    Keywords: Lepidoptera ; Noctuidae ; Heliothis zea ; Hymenoptera ; Trichogrammatidae ; Trichogramma pretiosum ; egg parasitoid ; sex pheromone ; kairomone ; host-community location ; olfactometer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Des expériences menées en olfactométrie avec le parasite oophage Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) et son hôte, Heliothis zea (Boddie) (Lepidoptera: Noctuidae) donnent les résultats suivants. La présence de la phéromone sexuelle de l'hôte réduit de façon significative le nombre de passages entre les champs odorisés. De mème, les parasites visitent plus fréquemment le champ qui dispense l'odeur de la femelle en appel que le champ témoin placé à l'opposé. Par ailleurs, le temps passé dans le champ qui contient la phéromone sexuelle émise par les femelles vierges en appel est significativement supérieur à la durée de visite des champs témoins. Si l'on utilise comme source d'odeur des femelles vierges qui ne sont pas en appel, la réponse est inversée, les parasites sont alors repoussés par l'odeur de ces papillons et le nombre de visites est distribué de façon aléatoire entre les quatre champs. Ces résultats sont discutés dans le contexte de l'écologie du comportement de recherche chez les parasites oophages.
    Notes: Abstract This paper presents results of olfactometer experiments with the egg parasitoid Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) and its host the corn earworm moth, Heliothis zea (Boddie) (Lepidoptera: Noctuidae). The sex pheromone of the host significantly reduced the total number of border crossings between odour fields in the olfactometer. Also, female parasitoids made significantly more visits to the calling moth odour field than to the opposite control field in the olfactometer. Further, the wasps spent significantly more time in the olfactometer field containing the sex pheromone released by calling virgin moths, than in control fields. If non-calling virgin moths were used as odour source, the response was reversed and wasps were repelled by the odour of the moths, and the numbers of visits were evenly distributed over the four flow fields. These results are discussed in the context of foraging ecology of egg parasitoids.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 46 (1988), S. 227-232 
    ISSN: 1570-7458
    Keywords: tri-trophic level interactions ; nicotine ; alkaloid ; Hyposoter annulipes ; Hymenoptera ; Ichneumonidae ; fall armyworm ; Spodoptera frugiperda ; Lepidoptera ; Noctuidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Des quantités croissantes de nicotine dans l'alimentation ont prolongé la durée du développement des chenilles saines, bien que l'effet ait chuté aux concentrations les plus élevées. Le sexe de la noctuelle n'a pas eu d'effet sur la durée du développement ou l'action de la nicotine. L'influence de la nicotine sur le poids des chrysalides est inhabituel, en ce sens que les chrysalides les plus lourdes ont été obtenues aux concentrations moyennes. Des hypothèses sont proposés sur l'origine de ce phénomène. La mortalité et la durée de développement de H. annulipes ont augmenté et le poids des adultes a diminué quand la concentration de l'aliment de l'hôte en nicotine s'est élevée. L'effet différente de la nicotine sur des générations successives a pu provenir de modifications de la toxicité de la nicotine en fonction de changements dans la qualité de l'aliment. Quoi qu'il en soit, l'augmentation de la concentration de la nicotine dans l'alimentation de l'hôte a eu un effet négatif cohérent sur la valeur adaptative de H. annulipes.
    Notes: Abstract Experiments were conducted to determine the influence of nicotine (at a range of concentrations) in the food of an herbivorous host on the development, size and survival of its parasitoid. Fall armyworms, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) were reared on diets of 0, 0.025, 0.050 and 0.075% nicotine and exposed to parasitism by Hyposoter annulipes (Hymenoptera: Ichneumonidae). As nicotine concentration increased parasitoid mortality and development time increased and adult weight decreased. Development time, pupal weight and survival were recorded for unparasitized armyworms. Unparasitized fall armyworms showed lengthened development and higher mortality but pupal weights were greatest at intermediate nicotine concentrations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 46 (1988), S. 221-225 
    ISSN: 1570-7458
    Keywords: Competitive interaction ; parasitoids ; Hymenoptera ; Braconidae ; Ichneumonidae ; Cotesia kazak ; Hyposoter didymator ; Heliothis armigera
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé Les interactions liées à la compétition entre deux parasitoïdes introduits d'H. armigera, le braconide C. kazak et l'ichneumonide H. didymator ont été examinées au laboratoire pour évaluer leur efficacité dans la nature. Séparément, C. kazak et H. didymator ont parasité respectivement 55% et 58% des chenilles d'H. armigera, et en combinaison, par multiparasitisme, 75%. Dans toutes les combinaisons de superparasitisme, après 24 h d'exposition, C. kazak a réduit de plus de 69% l'action de H. didymator. En plus de la mortalité des hôtes liées au succès du parasitisme, une mortalité larvaire élevée (23%) a été observée dans les cas de multiparasitisme, contre 10% avec parasitisme par une espèce. Cependant, quelle que soit la combinaison, la durée de développement de chacune des espèces n'a pas été modifiée. Puisque H. didymator s'est révélé intrinsèquement inférieur, il est suggéré de la lâcher le premier. C. kazak est un parasitoïde valable pour des libérations, là où déplacement compétitif de l'autre parasite n'est pas réalisé ou délibérément nécessaire.
    Notes: Abstract Competitive interaction between two introduced parasitoids of Heliothis armigera (Hb.) i.e. the braconid Cotesia kazak Telenga and the ichneumonid Hyposoter didymator (Thunb.) was studied in the laboratory. C. kazak and H. didymator individually parasitized about 55% H. armigera larvae, the combination of the two parasitoids gave more than 75% parasitism. C. kazak was found to be more effective, when the host was exposed to both parasitoids at the same time, reduced H. didymator population by 69% to 24 h. It is, therefore, better to release these two parasitoids individually in different locations to avoid any possible competitive interaction between the two. No difference in developmental time was observed irrespective of parasitoid sequence.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    Springer
    Entomologia experimentalis et applicata 47 (1988), S. 289-295 
    ISSN: 1570-7458
    Keywords: competition ; multiparasitization ; parasitoid ; physical attack ; Trieces tricarinatus ; Triclistus yponomeutae ; Hymenoptera ; Ichneumonidae ; Yponomeuta vigintipunctatus ; Lepidoptera ; Yponomeutidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Résumé La compétition entre les deux ichneumonides endoparasitoïdes solitaires Trieces tricarinatus Grav. et Triclistus yponomeutae Aeschl. a été examinée en élevant et disséquant des Yponomeuta vigintipunctatus Retz. attaqués le même jour par les deux parasitoïdes. Les résultats des dissections des hôtes multiattaqués ont été comparés à ceux des hôtes attaqués par un seul parasite, pour séparer la mortalité ou l'absence de parasitoïde provoquées par la compétition à celles dues à d'autres facteurs. On a constaté qu'un seul parasite était capable d'achever son développement. Dès que l'hôte était nymphosé et que les deux parasitoïdes étaient au premier stade larvaire, une des larves tuait sa compétitrice. Pour une fraction importante des larves éliminées, il a été possible de montrer qu'elles avaient été tuées par une aggression physique, pour les autres ce mode d'élimination était vraisemblable. L'espèce de parasitoïde qui survit dépend du nombre de jours entre la ponte des ichneumonides et la nymphose de l'hôte. Ce délai détermine le degré de développment des parasitoïdes et le moment réel de la compétition. Probablement, T. tricarinatus est le seul à survivre lorsque la nymphose de l'hôte a lieu avant l'éclosion des oeufs de T. yponomeutae.
    Notes: Abstract Competition between the solitary endoparasitoids Trieces tricarinatus (Gravenhorst) and Triclistus yponomeutae Aeschlimann (Hymenoptera: Ichneumonidae) results in the survival of one or the other of them. Once the host, Yponomeuta vigintipunctatus (Retzius) (Lepidoptera: Yponomeutidae) has pupated and both parasitoids have completed their development to first instar larvae, one of the parasitoid larvae kills the other. Which of the parasitoids survives depends on the number of days between parasitization and pupation. As a result of their type of development, this period determines the extent of development of the parasitoids at the moment of actual competition. Apparently, T. tricarinatus survives only if pupation of the host occurs before egg hatching of T. yponomeutae.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 149 (1988), S. 232-239 
    ISSN: 1432-072X
    Keywords: Turgor ; Glycine betaine ; K+ ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The accumulation of glycine betaine to a high internal concentration by Escherichia coli cells in high osmolarity medium restores, within 1 h, a subnormal growth rate. The experimental results support the view that cell adaptation to high osmolarity involves a decrease in the initiation frequency of DNA replication via a stringent response; in contrast, glycine betaine transport and accumulation could suppress the stringent response within 1–2 min and restore a higher initiation frequency. High osmolarity also triggers the cells to lengthen, perhaps via an inhibition of cellular division; glycine betaine also reverses this process. It is inferred that turgor could control DNA replication and cell division in two separate ways. Glycine betaine action is not mediated by K+ ions as the internal level of K+ ions is not modified significantly following glycine betaine accumulation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    ISSN: 1432-072X
    Keywords: Clostridium thermoaceticum ; Formyltetrahydrofolate synthetase ; Cloning ; Escherichia coli ; Thermostable protein ; Expression ; Acetogen
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Formyltetrahydrofolate synthetase (FTHFS) (EC 6.3.4.3), a thermostable protein of four identical subunits from Clostridium thermoaceticum was cloned into Escherichia coli SK1592. The clone (CRL47) contained a 9.5 kb EcoRI fragment of C. thermoaceticum DNA ligated into pBR322. It produced catalytically active, thermostable FTHFS, that was not found in E. coli SK1592 containing native pBR322. The identity of the expressed enzyme was confirmed by specific binding of rabbit polyclonal anti-FTHFS serum produced against C. thermoaceticum FTHFS. The specific activities (μmol·min-1·mg-1) of FTHFS in cell free extracts of CRL47 were 28–89 when assayed at 50°C and pH8. This was from 3–10-fold higher than in C. thermoaceticum extracts. FTHFS was purified to homogeneity from CRL47. The purified enzyme behaved during electrophoresis and gel chromatography and it had similar specific activity and thermostability as the enzyme purified from C. thermoaceticum.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 150 (1988), S. 499-503 
    ISSN: 1432-072X
    Keywords: Menaquinone ; Demethylmenaquinone ; Anaerobic respiration ; fnr gene ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Escherichia coli grown with glucose in the absence of added electron acceptors contained 3–4 times more naphthoquinones (menaquinone plus demethylmenaquinone) than in the presence of O2. Presence of electron acceptors resulted in a slight additional increase of the naphthoquinone content. A strain defective in the fnr gene, which encodes the transcriptional activator of anaerobic respiration, showed the same response. With fumarate or dimethyl sulfoxide present, 94% of the naphthoquinones consisted of menaquinone, while with nitrate up to 78% was demethylmenaquinone. With trimethylamine N-oxid as the acceptor the proportion was intermediate. From the donor substrates of anaerobic respiration only glycerol had a significant influence on the ratio of the contents of the 2 quinones. It is concluded that FNR, the gene product of the fnr gene, is not required for anaerobic derepression of naphthoquinone viosynthesis. Menaquinone appears to be involved specifically in the respiration with fumarate or dimethyl sulfoxide, and demethylmenaquinone in nitrate respiration. Both naphthoquinones appear to serve in trimethylamine N-oxide respiration.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    ISSN: 1432-072X
    Keywords: d-Cysteine desulfhydrase ; Cytosolic location ; 3-chloro-d-alanine sensitive ; 3-chloro-d-alanine dehydrochlorinase ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract d-Cysteine desulfhydrase of Escherichia coli W3110 ΔtrpED102/F′ ΔtrpED102 was physiologically characterized. It was found to be located in the cytosolic fraction, as 3-chloro-d-alanine dehydrochlorinase is. d-Cysteine desulfhydrase catalyzed not only the α,β-elimination reaction of O-acetyl-d-serine to form pyruvate, acetic acid and ammonia, but also the β-replacement reaction of O-acetyl-d-serine with sulfide to form d-cysteine. However, these reactions appeared not to proceed in vivo. No other activity of d-cysteine synthesis from O-acetyl-d-serine and sulfide was detected in a crude cell extract of E. coli which was immunotitrated with antibodies raised against the purified d-cysteine desulfhydrase. Although d-cysteine desulfhydrase catalyzes the degradation (α,β-elimination reaction) of 3-chloro-d-alanine, which is an effective antibacterial agent, E. coli W3110 ΔtrpED102/F′ ΔtrpED102 did not show resistance against 3-chloro-d-alanine. Therefore, d-cysteine desulfhydrase does not contribute to 3-chloro-d-alanine detoxification in vivo.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    ISSN: 1432-072X
    Keywords: Osmoadaptation ; Potassium uptake ; Glutamate synthesis ; Trehalose synthesis ; Internal pH ; Membrane potential ; Protonmotive force ; Proline uptake ; ProP system ; acr A-mutant ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sequence of events following the addition of 0.5 M NaCl to cells of Escherichia coli growing in a minimal mineral medium was investigated. Immediately after upshock the cells took up a large amount of K+ and synthesized approximately half the equivalent amount of glutamate concomitantly. After 30 min the cells started to synthesize trehalose, and after 2 h they had replaced most of their initial osmoprotectants by the carbohydrate. Cell trehalose was rapidly replaced by proline, taken up from the medium when added to the osmoadapting cells. The initial rate of this proline uptake was extremely rapid, and with rates observed of up to 0.6 mmolxmin-1xg-1 of cell protein it was approximately ten times faster than that reported in the literature for non-growing cells. These results indicate that for osmoadaptation of growing cells of E. coli the uptake of proline has priority over the synthesis of trehalose, which in its turn is preferred above K+ and glutamate as osmoprotectants. We observed that two mutants with unknown lesions, but which are known to be impaired in osmoadaptation, were inhibited in replacing K+ and glutamate by trehalose, indicating that this is the basis for their defect in osmoadaptation. Further experiments revealed that neither internal pH nor the membrane potential nor the transmembrane protonmotive force are likely to be involved in osmoadaptation in E. coli. However, during osmoadaptation a high internal potassium concentration appeared to stimulate the derepression of proline-uptake systems (mainly system ProP).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    ISSN: 1573-4919
    Keywords: Cytochrome P-450BM-3 ; Bacillus megaterium ; Escherichia coli ; protein charachterization ; recombinant DNA ; monoxygenase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Summary In two previous reports (Narhi LO, Fulco AJ, J. Biol. Chem. 261: 7160–7169, 1986; Ibid., 262: 6683–6690, 1987) we described the characterization of a catalytically self-sufficient 119000-dalton P-450 cytochrome that was induced by barbiturates in Bacillus megaterium. In the presence of NADPH and O2, this polypeptide (cytochrome P-450BM-3) catalyzed the hydroxylation of long-chain fatty acids without the aid of any other protein. The gene encoding this unique monooxygenase was cloned into Escherichia coli and the clone harboring the recombinant plasmid produced a protein that behaved electrophoretically and immunochemically like the B. megaterium enzyme (Wen LP, Fulco AJ, J. Biol. Chem. 262: 6676–6682, 1987). We have now compared authentic P-450BM-3 from B. megaterium and putative P-450BM-3 isolated from transformed E. coli and have found them to be indistinguishable with respect to chromatographic and electrophoretic behavior, reaction with specific antibody, prosthetic group (heme, FAD and FMN) analyses, spectra, enzymology, limited trypsin proteolysis and partial amino acid sequencing. We thus conclude that the P-450 cytochrome expressed by the transformed E. coli is essentially identical to native P-450BM-3 induced by barbiturates in B. megaterium. The evidence furthermore suggests that the primary amino acid sequence of this complex protein is alone sufficient to direct the proper integration of the three prosthetic groups and to specify folding of the polypeptide into the correct tertiary structure.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    ISSN: 1573-1561
    Keywords: Ants ; Monomorium ; Hymenoptera ; Formicidae ; 2,5-dialkylpyrrolidines ; 3,5-dialkylpyrrolizidines ; ant venom alkaloids ; chemotaxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A comparative analysis of the venom alkaloids produced by ants in the genusMonomorium (= Chelaner) collected on North Island and South Island, New Zealand, has been undertaken. All of the ants producetrans-2, 5-dialkylpyrrolidines along with 3,5-dialkylpyrrolizidines. The structures and sterochemistry of the novel alkaloidstrans-2-butyl-5-(8-nonenyl) pyrrolidine, (5E,8Z)-3,5-di(5-hexenyl)pyrrolizidine, and (5Z,8E)-3-methyl-5-(8-nonenyl)pyrrolizidine were established by unambiguous synthesis. The geographic distribution and the chemotaxonomic significance of the alkaloids produced by these ants are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    ISSN: 1573-1561
    Keywords: Fire bee ; Trigona (Oxtrigona) mellicolor ; Trigona (Oxtrigona) tataira ; honeybee ; Apis mellifera ; Hymenoptera ; Apidae ; mandibular gland secretion ; allomone ; nest plundering ; diketones ; (E)-3-heptene-2,5-dione ; (E)-3-nonene-2,5-dione
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Ten volatile compounds derived from the cephalic glands of the fire beeTrigona (Oxytrigona)mellicolor were bioassayed for possible allomonal activities facilitating nest plundering. Two diketones, (E)-3-heptene-2,5-dione and (E)-3-nonene-2,5-dione, caused the honeybeeApis mellifera to display avoidance behavior and reduced defensive behavior. These diketones are produced in relatively large quantities in fire-bee cephalic glands.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 14 (1988), S. 59-69 
    ISSN: 1573-1561
    Keywords: Atta cephalotes ; Hymenoptera ; Formicidae ; Attini ; leafcutter ants ; mutualism
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Four natural products, of varying activity as deterrents of leafcutter attack, were tested for their effects on ant survival and on the growth of the mutualistic attine fungus. The substances were incorporated into an artificial liquid diet for bioassays on the ants or included in an agar culture medium for fungus growth-inhibition studies. Three of the four compounds exhibited deleterious effects on either adult leafcutting ants or their mutualistic fungus, and there appeared to be some correlation between deterrency and activity in these toxicity assays. The implications of these findings for leafcutting ant foraging patterns are discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 14 (1988), S. 1583-1596 
    ISSN: 1573-1561
    Keywords: Microplitis demolitor ; Hymenoptera ; Braconidae ; Heliothis zea ; Lepidoptera ; Noctuidae ; Biological control ; artificial diet ; preflight behavior ; wind tunnels ; oviposition ; age ; chemosensory receptors ; chilling pupae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Heliothis zea (Boddie) larvae fed cowpea seedlings produced volatile semiochemicals to whichMicroplitis demolitor Wilkinson responded in a wind tunnel. However, mostM. demolitor females reared fromH. zea larvae fed an artificial diet were not responsive at emergence to the same volatile semiochemicals. A preflight contact with frass fromH. zea fed cowpea was needed to stimulate a response of sustained flight in a wind tunnel. The most consistent flight response was 7–10 days postemergence. Response resulting from both antennal and ovipositor contact with host frass during preflight stimulation was no better than from antennal contact alone. Chilling the parasitoid pupae rendered most of the emerging females unresponsive to volatile semiochemicals.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 14 (1988), S. 1239-1252 
    ISSN: 1573-1561
    Keywords: Third trophic level interaction ; Ostrinia nubilalis ; Lepidop-tera ; Pyralidae ; Diadegma terebrans ; Hymenoptera ; Ichneumonidae ; α-terthienyl ; berberine ; allelochemicals
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Two plant-derived allelochemicals, berberine and α-terthienyl (α- T), were tested for their effects on the European corn borer,Ostrinia nubilalis, and its endoparasitoidDiadegma terebrans. The compounds were administered to the host insect in meridic diets, and the responses of the host larvae and parasitoids reared from treated hosts were measured in terms of growth parameters and survival. InO. nubilalis, survival to pupation and adult emergence were reduced significantly by the inclusion of berberine and α-T in larval diets at a concentration of 100 μg/g. However, in the parasitoid, adverse effects were much more apparent with the α-T treatment than with the berberine treatment. α-T and one of its metabolites were found in host larvae and in emerged adult parasitoids and their cocoons. Berberine residues were not detected. The implications of these responses to compounds of widely differing physiological properties are discussed with reference to host-plant resistance and biological control.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    ISSN: 1573-5028
    Keywords: chloroplast ; cross-reaction ; Escherichia coli ; immunoblotting ; ribosome ; ribosomal protein S1
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Antibodies directed against E. coli ribosomal protein S1 were used in immunoblotting assays to search for an S1-like protein in the ribosome of spinach chloroplast. An immunological cross-reaction was reproducibly detected on the blots and inhibition experiments have demonstrated its specificity. The chloroplastic ribosomal protein which has epitopes common to antigenic determinants of the E. coli protein S1 was identified as being protein S2/S3.
    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 106 (1988), S. 183-202 
    ISSN: 1432-1424
    Keywords: proline transport ; proline utilization ; osmotolerance ; stress responses ; Escherichia coli ; Salmonella typhimurium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 211 (1988), S. 176-182 
    ISSN: 1617-4623
    Keywords: Escherichia coli ; Colicin B immunity gene cbi
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cells of Escherichia coli containing the cbi locus on plasmids are immune to colicin B which kills cells by dissipating the membrane potential through pore formation in the cytoplasmic membrane. The nucleotide sequence of the cbi region was determined. It contains an open reading frame for a polypeptide consisting of 175 amino acids. The amino acid sequence is homologous to the primary structure of the colicin A immunity protein. This, and the strong homology between the pore-forming domains of colicins A and B suggests a common evolutionary origin for both colicins. The immunity protein could be identified following strong overexpression of cbi. The electrophoretically determined molecular weight of 20 000 was close to the calculated molecular weight of 20 185. The protein contains four large hydrophobic regions. The immunity protein was localized in the membrane fraction and was mainly contained in the cytoplasmic membrane. It is proposed that the immunity protein inactivates the colicin in the cytoplasmic membrane.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 212 (1988), S. 378-381 
    ISSN: 1617-4623
    Keywords: Inducible mutagenesis ; Regionally targeted UV mutagenesis ; Escherichia coli ; Phage M13
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mutant forms of the glyU (glycyl tRNA) gene cloned in M13mp8 were subjected to uninduced targeted UV mutagenesis; i.e. phage particles were irradiated and used to infect unirradiated umuC + or irradiated umuC mutant cells. The irradiated phage carried GAG at the anticodon triplet and transitions to GAA were scored. The uninduced targeted mutation rate was reduced by altering the sequence of the gene in the vicinity of the target purine (Pu) residue. In particular a triplet of pyrimidines (PyPyPy) 5′ to the target G was changed to PyPuPy in order to prevent formation of cyclcobutane and 6-4 pyrimidine dimers close to the target. On this basis we suggest a mechanism for one type of uninduced regionally targeted UV mutagenesis.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    ISSN: 1617-4623
    Keywords: l-azetidine-2-carboxylate resistance ; Escherichia coli ; γ-glutamyl kinase ; Proline ; Saccharomyces cerevisiae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We constructed plasmids carrying the Escherichia coli proB gene that encodes γ-glutamyl kinase, under the control of the yeast GAL1 promoter. This construction was carried out with both the wild-type proB + gene and a mutant allele, proB74, that specifies an enzyme resistant to feedback inhibition by proline. Yeast pro1 mutants harboring these plasmids are proline prototrophs. We conclude that the pro1 mutation results in a deficiency in the γ-glutamyl kinase activity in Saccharomyces cerevisiae. Expression of the proB74 allele in yeast resulted in enhanced resistance to the proline analogue l-azetidine-2-carboxylate and in a 2.4-fold elevation of the intracellular free proline levels. This result suggests that γ-glutamyl kinase is the rate limiting step in proline biosynthesis in yeast.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    ISSN: 1617-4623
    Keywords: Escherichia coli ; Dictyostelium ; DNA gyrase ; Deletion ; Plasmid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary We constructed a recombinant plasmid containing the 2.1 kb HindIII fragment of plasmid pDG1, isolated from the cellular slime mold (Dictyostelium sp. strain GA11), and using pAG60 as cloning vector. We found that deletions of the recombinant plasmid took place frequently in Escherichia coli wild-type cells. However, the deletion was not observed when the plasmid was introduced into a strain that was an isogenic temperature-sensitive mutant of the gyrA gene. These results suggest that E. coli DNA gyrase is involved in the mechanisms of the deletion formation. It was shown that the 1.0 kb deletant derived from the 2.1 kb HindIII insert was produced by elimination of a 1.1 kb region. Sequence analysis of the deletants showed that cutting and rejoining took place between two out of the six nearly perfect direct repeats [21 bp palindromic sequences; AAAAAA(T/C)GGC(G/C)GCC(A/G)TTTTTT], located near the distal ends of the inverted repeats, preserving one copy of the repeats. These sequences consist of local short inverted repeats, where cutting and rejoining occur at one of the two regions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 213 (1988), S. 379-387 
    ISSN: 1617-4623
    Keywords: Stringent control ; RNA polymerase ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Previous studies on two Escherichia coli rpoB mutants, carrying single amino acid substitutions at approximate amino acid positions 736 and 906 in the β subunit, showed that these alterations in the RNA polymerase resulted in an apparent reduced response to valine-induced amino acid starvation in vivo and prevented ppGpp-mediated inhibition of transcriptional initiation at stable RNA promoters in vitro. These observations suggested that the mutations had altered either the ppGpp binding site or the promoter selectivity of the enzyme. The in vivo analysis presented here indicates that these mutants encode an RNA polymerase that responds normally to changes in the level of ppGpp; their apparent relaxedness is due to a reduced accumulation of ppGpp during isoleucine starvation. Thus, there is no indication that the mutations have altered ppGpp binding sites. These observations and the difference between in vitro and in vivo results can be explained by the assumption that the mutations produce an extended ppGpp-dependent pausing of RNA polymerase during the transcription of unstable RNA. Comparison of the vivo and in vitro effects of ppGpp on rrn transcription further suggests that these reflect different phenomena, although in both cases ppGpp inhibits rrn transcription.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 214 (1988), S. 62-67 
    ISSN: 1617-4623
    Keywords: Mutagenesis ; Inosine ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two complementary 24 base single stranded oligonucleotides containing randomly located inosine residues were synthesized in vitro. Once annealed, the two oligonucleotides were cloned into derivatives of ColE1 and transformed into Escherichia coli. Sequence analysis of 157 clones yielded 305 mutations. The pattern of the mutations revealed the following: (1) The frequency of inosine induced mutations was significantly less than predicted from its content in the oligonucleotides; (2) Inosine incorporation resulted almost exclusively in base changes to guanine; (3) The mutation distribution is biased towards A/T to G/C substitutions; (4) There were reproducible position biases; and (5) There was a reproducible strand bias which was independent of the cassette orientation with respect to the plasmid origin of replication.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    ISSN: 1617-4623
    Keywords: N-ethyl-N′-nitro-N-nitrosoguanidine ; 1-(2-hydroxyethyl)-1-nitrosourea ; Mutations ; Escherichia coli ; DNA sequencing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary DNA sequencing was used to determine the specific types of DNA base changes induced following in vivo exposure of Escherichia coli to the ethylating agent N-ethyl-N′-nitro-N-nitrosoguanidine (ENNG) and the hydroxyethylating agent 1-(2-hydroxyethyl)-1-nitrosourea (HENU) using the xanthine guanine phosphoribosyltransferase (gpt) gene as the genetic target. We observed that 22/30 of the ENNG-induced mutations were GC→AT transitions, 4/30 were AT→GC transitions, 3/30 were AT→TA transversions, and 1/30 was an AT→CG transversion. We observed that 37/40 HENU-induced mutations were GC→AT transitions and that the remaining 3/40 were AT→GC transitions. A majority of the GC→AT transitions induced by ENNG and HENU (68% and 73%, respectively) occurred at the second guanine of the sequence 5′-GG(A or T)-3′; this sequence specificity was similar to that previously seen with the alkylating agents N-methyl- and N-ethyl-N-nitrosourea (MNU and ENU) and N-methyl-N′-nitro-N-nitrosoguanidine (MNNG). A DNA strand preference for the G→A changes (antisense strand), previously noted for MNU, ENU, and MNNG, was observed following exposure to HENU and ENNG. The AT→GC transitions induced by ENNG, HENU, and ENU also exhibit a sequence specificity with 13/13 mutations occurring at the T of the sequence 5′-NTC-3′. A strand preference was not apparent for these mutations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 213 (1988), S. 99-104 
    ISSN: 1617-4623
    Keywords: Promoters ; Escherichia coli ; Proteus vulgaris ; Hemolysin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The hemolytic activity of Escherichia coli and Proteus vulgaris is determined by common contiguous genes encoding synthesis (hly C, hly A) and specific secretion (hly B, hly D) of active hemolysin. Nevertheless, the hlyC-proximal DNA sequences directing production of the homologous hemolysins by the recombinant DNAs P. vulgaris pVU763-709 and E. coli pANN202-312 showed no extensive homology. Primer extension and S1 nuclease protection were used to define in the two sequences the 5′ termini of hly transcripts synthesized in vivo and thus to infer the active hly promoters sequences. The E. coli hly C upstream region contained three separate promotors directing in vivo hly transcription, while the corresponding transcription of the P. vulgaris hly operon originated from a single distinct promotor, the-35 and-10 sequences of which formed part of an inverted repeat sequence. Elevated hemolytic activity caused by upstream Tn5 insertions in pVU763-709 resulted from increased transcription from this promotor.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 214 (1988), S. 148-152 
    ISSN: 1617-4623
    Keywords: RNA polymerase ; Transcription ; Positive regulation ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The specificity of the transcription defect caused by the rpoA341 (phs) allele has been investigated. Three apparently unlinked genetic systems have been found to be impaired in their transcription by this mutant allele of the alpha subunit of RNA polymerase. These three systems, the melAB operon the cysA locus and the ara regulon, are apparently unrelated other than by their requirement for a regulon-specific positive regulator for the initiation of transcription. Expression of the gene for the positive regulator does not appear to be significantly affected in any of the three systems. However, mutations that render expression of the araBAD operon independent of the regulatory protein also confer insensitivity to the rpoA341 allele. The siginificance of these observations is discussed in the context of models of positive regulation.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 215 (1988), S. 156-160 
    ISSN: 1617-4623
    Keywords: Ionising radiation ; Gene cloning ; DNA repair ; Escherichia coli ; Mitomycin C
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A segment of the Escherichia coli genome which complements the ionising radiation sensitivity of the rorB mutation was cloned into pBR322. This DNA segment also complements the mitomycin C sensitivity of the rorB mutation. The gene was subcloned until defined in a fragment of 1.05 kb. Only one gene product, a protein of approximately 16.5 kDa, was found on maxicell analysis of the various subclones. Iso-electric focusing of this gene product suggests it may function in a complex.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 211 (1988), S. 1-7 
    ISSN: 1617-4623
    Keywords: Nalidixic acid resistance ; Quinolones ; gyrA ; Nucleotide sequence ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary DNA fragments of 8.5 kb containing the gyrA gene were cloned from Escherichia coli KL-16 and from four spontaneous gyrA mutants which showed various levels of resistance to quinolones. The gyrA gene was situated at about 4 kb in front of the nrdA gene and transcribed counterclockwise on the E. coli chromosome. It encoded a polypeptide of 875 amino acids with a molecular weight of about 97000. The four gyrA mutations were located strikingly close to one another within a small region near the N-terminus of the gyrA polypeptide, i.e., nucleotide changes from C to T, from C to G, from G to T and from G to T at nucleotides 248, 248, 318 and 199, respectively, resulting in amino acid changes from Ser to Leu, from Ser to Trp, from Gln to His and from Ala to Ser at amino acids 83, 83, 106 and 67, respectively. These mutations were situated in the relatively hydrophilic regions of the GyrA polypeptide and close to Tyr at amino acid 122 which has been shown to be the site covalently bound to DNA.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 211 (1988), S. 459-464 
    ISSN: 1617-4623
    Keywords: Chloroplast ; DNA-dependent RNA polymerase ; Initiation factor ; Transcription ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The 80 000 x g supernatants of spinach leaf homogenates contain polypeptides that are immunologically related to the ββ′, α and σ subunits of Escherichia coli RNA polymerase. The σ-like (90 kDa and 33 kDa) and α-like (38 kDa) polypeptides are separated from ββ′-like ones by chromatography on Heparin-Sepharose or Servacel-PEI. If a protein fraction containing the α- and σ-like polypeptides is added to transcriptionally active purified chloroplast polymerase (consisting of the ββ′-like 150/145 kDa and 80 kDa polypeptides and the 110/102 kDa polypeptides the latter two being not homologous to polypeptides of E. coli polymerase) a correct initiation and transcription of the spinach chloroplast rbcL gene is obtained. Chloroplast protein fractions containing the σ-like polypeptide(s) also enhance correct transcription initiation when they are combined with E. coli RNA polymerase.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 212 (1988), S. 1-5 
    ISSN: 1617-4623
    Keywords: Cytochrome b 561 ; Diheme b-type cytochrome ; cybB gene ; Escherichia coli ; DNA sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The complete nucleotide sequence of the Escherichia coli cybB gene for diheme cytochrome b 561 and its flanking region was determined. The cybB gene comprises 525 nucleotides and encodes a 175 amino acid polypeptide with a molecular weight of 20160. From its deduced amino acid sequence, cytochrome b 561 is predicted to be very hydrophobic (polarity 33.7%) and to have three membrane spanning regions. Histidines, canonical ligand residues for protohemes, are localized in these regions, and the heme pockets are thought to be in the cytoplasmic membrane. No significant homology of the primary structure of cytochrome b 561 with those of other bacterial b-type cytochromes was observed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 211 (1988), S. 320-325 
    ISSN: 1617-4623
    Keywords: Tn21 integrase ; Site-specific recombination ; Transposon evolution ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The IncW plasmid R388 and the DNA region of Tn21 containing the Smr and the Sur genes are capable of RecA-independent recombination. This recombination occurs at a relatively high frequency (up to 10-4 recombinants per recipient molecule) and results in integration of the two plasmids. No detectable repeats are formed in the process. The crossover points have been confined to a 0.4-kb homologous segment in both plasmids which contains a 59-bp DNA sequence presumably involved in the acquisition of new genes by Tn21 and its relatives (Cameron et al. 1986). It is likely that the recombination occurs precisely at this point. At least one trans-acting function (an integrase) is required for the site-specific recombination. It has been localized to a 1456-bp BstEII-BamHI fragment of Tn21 and can efficiently complement the integration of plasmids containing the integration site.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 214 (1988), S. 379-388 
    ISSN: 1617-4623
    Keywords: putP ; putA ; putC ; Escherichia coli ; Promoter regions of putA and putP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effects of regulatory proteins on the expression of putP and putA were studied using put-lacZ fusion genes. The expression of the putP-lacZ gene was activated by the glnG gene product and the catabolite gene activator protein (CAP). The putA gene product inhibited activation of putP-lacZ gene expression by CAP or the glnG gene product and its inhibition was greater in the absence of proline. The expression of the putA-lacZ gene was activated by CAP and repressed by the glnG gene product. The putA gene product acted as a repressor in the absence of proline, but not in its presence. Studies using put-lacZ fusion genes with upstream deletions showed that the region required for the activation of putP by CAP was within 234 bp upstream of the translational initiation site and that that for the activation of putP was within 107 bp upstream of the translational initiation site of the putA gene. This supported the suggested locations of CAP binding sites. The region required for induction of putP and putA expression by proline was located at the Hpal site 182 bp upstream of the translational starting site of putA, suggesting that a sequence of dyad symmetry located 1 bp to the left of the HpaI site is a candidate for the binding site of the putA gene product.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Simultaneous distillation-extraction ; Cheese volatiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simultaneous distillation-extraction apparatus proposed by Godefroot has been used for the GC study of volatile components of cheese. 5–10 g of cheese provide a fraction that can be directly injected into a GC or a GC/MS. Two capillary columns (SE-30 and SP-1000) were evaluated, the second one being adequate for quantitative determinations. Camphor was used as internal standard. The coefficients of variation ranged from 1.4 to 11.8. The technique can be used as a fast method for the characterization of cheeses from their volatile component concentrations.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 1087-1088 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Log plot ; Homologous series
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The slope of the log plot of the adjusted retention time of a homologous series usually varies from that of the n-alkane series by no more than 2%, though with unusual interactions between the functional group and the stationary phase the difference may be as high as 7%.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Preparative scale separations ; Plate model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Two close-boiling materials, diethyl ether (DEE) and dichloromethane (DCM), were separated to investigate the effects of the pure components and the mixture on elution in preparative gas-liquid chromatography. Nitrogen was used as the carrier gas, and the chromatographic column (1 cm I.D. and 0.75m length) was packed with Chromosorb A with different quantities of dinonyl phthalate stationary phase and particle sizes. Below ca. 7% (by wt.) of feed concentration, the experimental elution curves of pure DEE and DCM were almost the same as those of the mixture, and the theoretical plate model can be used successfully to predict the elution curves.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 404-408 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Silica surface modification ; Hexamethylcyclotrisilazane ; Hexamethyldisilazane ; Support materials
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The paper is concerned with the structure of an organic layer bonded to the silica surface modified with silazanes. The changes of the retention volumes of hydrocarbons is studied for the silicas modified with hexamethylcyclotrisilazane, hexamethyldisilazane and their mixtures. It is shown that most of the carbon in the layer after hexamethylcyclotrisilazane modification is bonded to the surface by Si−O−Si bonds. This fact supports the assumption of a fragmentation of the cyclosilane used for modification.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Statistical criteria ; Non-linear models ; Constants for n-alkane retention curve ; Multiparametric least-squares adjustment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Multiparametric, least-squares, regression treatment of G.C. data is extended to describe deviations from the usual linear model. Through statistical evaluation of results, four parameters models are generally found adequate and the use of higher degree empirical models is discouraged.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 539-542 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Temperature programming ; Retention index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is presented for the calculation of retention indices at an assigned temperature from temperature-programmed data. If the retention times at two different program rates for the solutes and the n-alkanes are known, the retention indices at an assigned temperature can be calculated directly.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 26 (1988), S. 125-132 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Non-equilibrium frontal chromatography ; Nonlinear isotherms ; Variable velocity ; Multicomponent mixtures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The paper presents a classification of various theoretical models for multicomponent gas chromatography at u=var for high concentrations of the mixture components with consideration of the major distinctive features of the interphase mass exchange inside the porous grains of the adsorbent and outside them within the porous medium of the chromatographic column. It has been shown that the conditions determining a given front behaviour of multicomponent gas mixture at u=var depend on: theoretical models for the kinetics and dynamics of adsorption; the values of mass exchange parameters inside the porous grains and in the porous medium. Formulae have been derived for calculating the values of the quantities characterising the frontal behaviour in the stage of adsorption and desorption of multicomponent mixture at u=var.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 211 (1988), S. 138-142 
    ISSN: 1617-4623
    Keywords: Escherichia coli ; DnaA ; Replication initiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Overexpression of DnaA protein from a multicopy plasmid accompanied by a shift to 42°C causes initiation of one extra round of replication in a dnaA + strain grown in glycerol minimal medium. This extra round of replication does not lead to an extra cell division, such that cells contain twice the normal number of chromosomes.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    ISSN: 1617-4623
    Keywords: Escherichia coli ; Recombination ; DNA repair ; recD
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary DNA repair and recombination were investigated in a recD mutant of Escherichia coli which lacked the nuclease activity of the RecBCD enzyme. The resistance of this mutant to ultraviolet (UV) light was shown to be a function of recJ. A recD recJ double mutant was found to be more sensitive to UV radiation than a recB mutant, whereas recD and recJ single mutants were resistant. Recombination in conjugational crosses with Hfr donors was also reduced in recD recJ strains, but the effect was modest in comparison with the sensitivity to UV. Within certain limits, mutations in recF, recN, recO, lexA and ruv did not affect sensitivity to UV and recombination in a recD mutant any more than in a recD + strain. The possibility that recD and recJ provide overlapping activities, either of which can promote DNA repair and recombination in the absence of the other, is discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 215 (1988), S. 165-172 
    ISSN: 1617-4623
    Keywords: Escherichia coli ; Repetitive protein ; Heterologous gene expression ; Protein engineering ; inaZ gene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ice nucleation gene inaZ, from Pseudomonas syringae S203, was manipulated to produce a series of defined rearrangements in its coding sequence without changing the reading frame. The effects of these mutations on the ice nucleation phenotype were determined in a heterologous host, Escherichia coli K12. Deletions which disrupted the periodicity of 16 codons, in a repetitive region of inaZ, caused the frequencies of ice nuclei in the bacterial population to be significantly depressed; the nuclei with thresholds at warmer temperatures were most affected. In contrast, when the periodicity was left intact, deletions and duplications in the same region had only slight effects on nucleation activity. Deletions removing part or all of one of the nonrepetitive regions (that encoding the amino-terminal domain of the InaZ protein) did not abolish nucleation activity, but caused it to be limited to cooler threshold temperatures. In contrast, the non-repetitive carboxy-terminal domain of the InaZ protein was shown to be essential for ice nucleation at all temperatures. The differential requirements (for periodicity, and for the amino-terminus) in forming nuclei with different thresholds may be significant for understanding what determines the threshold temperature of an ice nucleus.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    Springer
    Molecular genetics and genomics 215 (1988), S. 69-75 
    ISSN: 1617-4623
    Keywords: FhuA receptor protein ; Export ; Assembly ; Outer membrane ; Escherichia coli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The FhuA protein (formerly TonA) is located in the outer membrane of Escherichia coli K12. Fusions between fhuA and phoA genes were constructed. They determined proteins containing a truncated but still active alkaline phosphatase of constant size and a variable FhuA portion which ranged from 11%–90% of the mature FhuA protein. The fusion sites were nearly randomly distributed along the FhuA protein. The FhuA segments directed the secretion of the truncated alkaline phosphatase across the cytoplasmic membrane. The fusion proteins were proteolytically degraded up to the size of alkaline phosphatase and no longer reacted with anti-FhuA antibodies. The fusion proteins were more stable in lon and pep mutants lacking cytoplasmic protease and peptidases, respectively. The larger fusion proteins above a molecular weight of 64000 dalton were predominantly found in the outer membrane fraction. They were degraded by trypsin when cells were converted to spheroplasts so that trypsin gained access to the periplasm. In contrast, FhuA protein in the outer membrane was largely resistant to trypsin. It is concluded that the larger FhuA‘-’PhoA fusion proteins were associated with, but not properly integrated into, the outer membrane.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    ISSN: 1617-4623
    Keywords: Escherichia coli ; Ionising radiation ; Mutation ; DNA repair
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Escherichia coli K803 cells were mutagenized and screened for the presence of clones sensitive to ψ-rays but not to ultraviolet light. One new mutant of this type, named rorB, was isolated. This mutant is both cross-sensitive to mitomycin C and shows reduced conjugal recombination frequencies, but to a lesser extent than the phenotypically similar mutant recN. Unlike previously reported mutants of E. coli or yeast with an enhanced sensitivity to ionising radiations, rorB appears to be near wild type in ability to rejoin DNA double-strand breaks. The rorB gene maps close to ilvGEDAC at 84.5 min of the E. coli chromosome.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    Springer
    Journal of bioenergetics and biomembranes 20 (1988), S. 41-58 
    ISSN: 1573-6881
    Keywords: F1-ATPase ; H+-ATPase ; Escherichia coli ; uni-site catalysis ; unc operon ; chemical modification ; ATP synthase ; ATP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract We have reviewed recent molecular biological studies on F1-ATPase ofEscherichia coli and emphasized the advantages of using the bacterium in studies on this important enzyme. All subunits had homologies of varied degrees with those from other organisms. Mutations of F1 subunits caused defects in catalysis and assembly. Defects of the mutant enzymes were studied extensively together with the determination of the amino acid substitutions. Extensive molecular biological studies may help greatly in understanding the normal mechanism and assembly of the complex.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    Springer
    Ecological research 3 (1988), S. 217-226 
    ISSN: 1440-1703
    Keywords: Cardiochiles nigriceps ; Hymenoptera ; Mating system ; Parasitoids ; Protandry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A laboratory study was conducted of the emergence times and mating success ofCardiochiles nigriceps Viereck (Hymenoptera: Braconidae), a larval parasitoid of the tobacco budworm,Heliothis virescens (F.) (Lepidoptera: Noctuidae), and in view of this information, the parasitoid's mating system was explored. Observations on laboratory populations ofC. nigriceps confirmed the occurrence of two types of protandry, i.e. seasonal and diurnal; males emerged 2 days before females in a generation, and emerged about 1 hr before females on a given day. An experiment on mating success showed that newly emerged females are not receptive to males that emerged 1 hr earlier, but that these males and females often mate successfully after 1 more hr. The experiment also showed that 1- to 5-day-old males are more successful than 1-hr-old males in mating with 0- to 1-hr-old females. Thus, it is argued that males emerging on a given day have a disadvantage in competition for mates with males that emerged days earlier, and that this disadvantage may serve as a selection pressure toward diurnal protandry. A monogamous mating system for females ofC. nigriceps is suggested because sexual selection would be expected to be strong in species exhibiting both seasonal and diurnal protandry. A possibility of a sibling mating system inC. nigriceps is questioned partly because newly emerged females are unreceptive to males that emerged 1 hr earlier and partly because this parasitoid is solitary in what is considered highly dispersed hosts in the field.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 14 (1988), S. 2185-2196 
    ISSN: 1573-1561
    Keywords: Hymenoptera ; Formicidae ; Pogonomyrmex ; Hepatica americana ; ants ; Ranunculaceae ; diglyceride ; elaiosome ; myrmecochory ; seed dispersal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract We investigated the chemical basis for ants carrying the seeds ofHepatica americana, an ant-dispersed plant of eastern North America. A laboratory bioassay of seed and elaiosome extracts was based on the distance test items were carried byPogonomyrmex rugosus. Ants responded equally to isolated elaiosomes and to the diglyceride fraction. Diolein was a major component of the diglyceride fraction, which is consistent with a finding that 1,2-diolein releases seed-carrying byAphaenogaster rudis. Ants' response to the free fatty acid fraction was less intense. Gas chromatography of the fatty acid fraction indicated that oleic acid was a primary component, and oleic acid is known to elicit necrophoric behavior. No evidence supports an earlier suggestion that ricinoleic acid stimulates seed-carrying behavior. Ants failed to respond to seeds from which elaiosomes were removed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 14 (1988), S. 713-721 
    ISSN: 1573-1561
    Keywords: Larch sawfly ; Pristiphora erichsonii ; Hymenoptera ; Tenthredinidae ; 3-carene-10-al ; benzaldehyde ; bornyl acetate ; larval snap-bending
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The emission of species-specific odors byPristiphora erichsonii andP. wesmaeli is accompanied by a characteristic defensive behavior called “snap bending.” When the larvae are disturbed, blends of volatile compounds are emitted from ventral glands. The odor ofP. erichsonii, a colonial species, is composed of bornyl acetate, borneol,trans-pinocarveol, myrtenol, benzaldehyde, and tetradecyl, hexadecyl, and octadecyl acetates, whereas that of the solitaryP. wesmaeli is composed of 3-carene-10-al, linalool, myrtenal, and benzaldehyde. The role of these compounds in the defensive behavior of the larvae is discussed.
    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 14 (1988), S. 957-962 
    ISSN: 1573-1561
    Keywords: (E)-9-oxo-2-decenoic acid ; tritium labeling ; Apis mellifera ; primer pheromone ; radiosynthesis ; Hymenoptera ; Apidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A short synthesis of [4,5-3H2] (E)-9-oxo-2-decenoic acid (ODA), a high-specific-activity tritium-containing isotopomer of the queen bee pheromone, is described. Catalytic tritiation of the ketal of ethyl 9-oxo-4-decenoate introduces tritium into two positions, one of which is completely unactivated. Subsequent transformation by selenation, oxidation, and hydrolysis affords the labeled 9-ODA at 〉60 Ci/mmol. The material is suitable for biochemical studies of binding and catabolism in ovarian, antennal, and other target tissues.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 14 (1988), S. 2099-2107 
    ISSN: 1573-1561
    Keywords: Honeybee ; Apis mellifera ; Hymenoptera ; Apidae ; alarm pheromones ; wax compounds ; antiaggression pheromone ; exocrine glands ; chemisociality
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract A dazzling variety of honeybee behaviors are triggered by pheromones produced by disparate exocrine glands. A multiplicity of chemical releasers of social behavior has been demonstrated to regulate a diversity of societal interactions, and many of these compounds are synthesized with great caste specificity. Recent investigations have resulted in the identification of a host of new compounds that are products of either worker or queen honeybees. This report fractionates these newly identified exocrine products according to their glandular proveniences and focuses on both the structural and behavioral eclecticism that characterizes these chemical signaling agents.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    ISSN: 1573-1561
    Keywords: Hymenoptera ; Braconidae ; Microplitis croceipes ; Heliothis zea ; parasitoid ; host selection ; volatile attractant ; olfactometer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The response ofMicroplitis croceipes (Cresson) to odors from a plant-host complex was investigated using a four-choice olfactometer. Female, but not male, parasitoids responded in a dose-dependent fashion to volatiles from the plant-host complex and oviposition experience enhanced this response. Female age had no apparent effect on the response. Both artificially damaged leaves and frass elicited positive responses but of lower magnitude than those elicited by the plant-host complex. Volatiles collected from the plant-host complex placed on filter paper also elicited positive responses by female parasitoids.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 14 (1988), S. 517-527 
    ISSN: 1573-1561
    Keywords: Tetraponera ; ant ; alkaloids ; poison gland ; contact poison ; tetraponerine ; Hymenoptera ; Formicidae ; Pseudomyrmecinae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The Neo-Guinean pseudomyrmecine ant,Tetraponera sp. utilizes its modified sting to smear upon enemies a contact poison with strong deterring and toxic properties. The venom, which originates from the poison gland, contains a mixture of eight closely related, alkaloids (tetraponerine-1 to -8). The structure of tetraponerine-8 was established by an X-ray diffraction analysis and was reported previously. The structure of five other members of the series has now been determined by comparison of their spectral properties with those of tetraponerine-8 and of model compounds.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 14 (1988), S. 825-838 
    ISSN: 1573-1561
    Keywords: Solenopsis invicta ; Hymenoptera ; Formicidae ; imported fire ant ; Dufour's gland ; trail pheromone ; pheromone ; (Z,E)-a-farnesene ; sesquiterpene
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract TheSolenopsis invicta trail pheromone is synthesized by the Dufour's gland and is released through the sting apparatus. The recruitment subcategory of theS. invicta trail pheromone was shown to be composed of a mixture of the orientation pheromone, (Z,E)-α-farnesene and an unidentified homosesquiterpene consisting of three rings and one double bond (C-1). C-1 is present in worker Dufour's glands at only 75 pg per worker equivalent. This is the first report that demonstrates that different exocrine products from the same gland control different subcategories of behavior related to mass recruitment.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    ISSN: 1573-1561
    Keywords: Microplitis croceipes ; Microplitis demolitor ; Hymenoptera ; Braconidae ; parasitoids ; semiochemicals ; kairomones ; 13-methylhentriacontane ; stereoisomers ; enantiomers ; Heliothis zea ; Lepidoptera ; Noctuidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The responses ofMicroplitis croceipes (Cresson) andMicroplitis demolitor Wilkinson to theR andS stereoisomers of the kairomone 13-meth-ylhentriacontane were evaluated. Singly and in combination at 5, 50-, and 500-ng dosage levels each were tested. There was a linear dosage response by both species to the three dosages. Furthermore, there was no difference between responses to the two stereoisomers or their combination by either species at any dosage level. The effects of the two stereoisomers were fully interchangeable and additive. This is the first report of parasitoid responses to stereoisomers of a kairomone.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    ISSN: 1573-1561
    Keywords: Thoracic glands ; secretion ; Xylocopa varipuncta ; Xylocopa micheneri ; Hymenoptera ; Anthophoridae ; terpenoid ; fatty acid ester ; fatty alcohol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Some male carpenter bees (Xylocopa spp.) possess massive propodeal exocrine glands that produce copious quantities of multicomponent blends of lipoidal material. Some of these compounds are volatile, producing a “flowery” aroma that can be easily detected several meters downwind from a territorial male. Chemical characterization of these secretions showed them to be blends of terpenoid compounds or fatty acid derivatives. InX. varipuncta, the mixture is composed of alltrans-geranylgeraniol, alltrans-farnesal, and an isomer of 3,7, 11-trimethyl-2,7,10-dodecatrienal in an approximate 9∶6∶1 ratio. The secretion ofX. micheneri contains isopropyl oleate, (Z)-11-eicosen-1-ol, oleyl alcohol, and methyl palmitate at approximately 63∶24∶11∶1. We hypothesize that these compounds act as pheromones that aid in attracting and holding conspecific females to symbolic nonresource encounter sites where mating occurs. They also appear to have utility as chemotaxonomic markers at the subgeneric level.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 14 (1988), S. 1475-1484 
    ISSN: 1573-1561
    Keywords: Kairomone ; oviposition ; parasitoid ; Ascogaster reticulatus ; Hymenoptera ; Braconidae ; smaller tea tortrix ; Adoxophyes sp. ; Lepidoptera ; Tortricidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract An artificial egg with a Parafilm membrane was devised for the oviposition ofAscogaster reticulatus Watanabe (Hymenoptera: Braconidae), an egg-larval parasitoid of the smaller tea tortrix,Adoxophyes sp. (Lepidoptera: Tortricidae). Both external and internal kairomones were essential. The external kairomone, needed for host location and acceptance, was extracted with 70% ethanol, and the internal kairomone, needed for oviposition, was extracted with water. Female parasitoids responded to the external kairomone and oviposited through the membrane into the artificial egg when the supernatant of host egg-mass homogenate was inside, whereas they did not when water or saline solutions were inside. Thus an internal kairomone is responsible for the oviposition in the host egg. The internal kairomone apparently was not specific for the host egg mass because oviposition activity was found not only in egg, larval, and pupal stages of the host, but also in larvae of other species of Lepidoptera and Coleoptera.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    ISSN: 1573-1561
    Keywords: Biosteres longicaudatus ; Biosteries tryoni ; Biosteres arisanus ; Hymenoptera ; Braconidae ; Hagen's gland ; ethyl octanoate ; ethyl octenoate ; octan-4-olide ; dodecan-4-olide ; (3aα,5β,6aα)-5-butyltetrahydrofuro[3,2-b]furan-2(3H)-one ; (3aα,5β,6aα)-5-hexyltetrahydrofuro[3,2-b]furan-2(3H)-one
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The morphology and chemical content analysis of Hagen's glands of the braconid waspsBiosteres longicaudatus, B. tryoni, andB. arisanus were shown to be useful taxonomic markers.B. longicaudatus glands contain two components tentatively identified as (3aα,5β,6aα)-5-butyltetrahydro-furo[3,2-b]furan-2(3H)-one and a corresponding 5-hexyl derivative, whileB. tryoni glands contained dodecan-4-olide andB. arisanus glands contained ethyl octanoate, ethylZ-4-octenoate, and octan-4-olide.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    ISSN: 1573-1561
    Keywords: Solenopsis invicta ; Hymenoptera ; Formicidae ; brood recognition ; pheromone ; fire ant ; behavior ; olfaction ; orientation ; bioassays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Behavioral and electrophysiological studies with live intact larvae and larval rinses of the red imported fire ant,Solenopsis invicta Buren, give undeniable evidence of a volatile material associated with the larvae of the ant that is capable of eliciting a response from brood-tending workers. In a Y-tube bioassay, worker ants were attracted equally to an airstream blown over sibling larvae or heterocolonial larvae. Workers were also attracted to a rinse of the larvae in a spot bioassay, aggregated about a piece of surrogate brood in another bioassay, and retrieved surrogate brood treated with the rinse material. A dose-response curve constructed from electroantennograms of workers revealed a receptor response of 1–100 brood equivalents.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Electronic Resource
    Electronic Resource
    Springer
    Antonie van Leeuwenhoek 54 (1988), S. 285-299 
    ISSN: 1572-9699
    Keywords: fimbriae biogenesis ; genetic organization ; gene clusters ; protein translocation ; Escherichia coli ; adhesion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The genetic organization of the determinants of type 1, K88ab, K99 fimbriae and P(pap)pili of Escherichia coli is presented. The functions of the various gene products are described and a model for the process of fimbriae biogenesis is presented and discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    ISSN: 1572-9699
    Keywords: Escherichia coli ; urinary tract infection ; dogs ; fimbriae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A number of Escherichia coli strains have been isolated from dogs with urinary tract infections. These strains have been characterised with respect to their O, K, H, and fimbrial antigens, colicin production, antibiotic resistance, plasmid content and their ability to haemagglutinate erythrocytes from various species. Crossed immunoelectrophoresis of fimbrial extracts, as well as the reaction of partly purified fimbriae of a number of these strains with monoclonal antibodies revealed homology or a strong crossereaction with an F12 fimbrial subunit protein of human uropathogenic E. coli strains. Unlike human F12 fimbriae producing strains, the dog isolates did agglutinate dog erythrocytes in the presence of D-mannose but not human erythrocytes, indicating that the adhesin carried by these strains is different from the adhesin on fimbriae of human uropathogenic E. coli. Similar indications were obtained from experiments with latex beads coated with the receptor for P-fimbriae. These beads were agglutinated by Escherichia coli strains from human urinary tract infections, but not by the dog isolates described here. Preliminary adhesion experiments of human and dog Escherichia coli to human bladder epithelial and canine kidney epithelial cells also showed differences in adhesion depending on the origin of the strain tested.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 21-24 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Sample concentration ; Chromatographic evaporation ; Solvent effect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Several micro-techniques for the removal of solvent from dilute solutions of volatile compounds have been compared. Large solute losses were experienced when the conventional blow-down technique was applied. Better yields could be obtained with static evaporation procedures, as long as an effective reflux was maintained. However, careful optimization of the vessel design and operating conditions is necessary. The most efficient volume reduction technique was shown to be chromatographic evaporation. Quantitative recoveries were obtained for the compounds tested and the process was significantly faster than static concentration. Moreover, operating conditions (gas flow, temperature) are less critical. With modifications, the principle can be used for the concentration of large sample volumes down to a few microliters.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Stationary phase polarity ; Polarity parameters ; Structure-retention relationships
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The new stationary phase polarity parameters BN and BS evaluated from the concept of the electric intermolecular interactions are used to describe the polarity of polyoxyethylene glycol dialkyl ethers and their sulphur analogs. Relations between the discussed parameters and accepted measures of surfactants' polarity are presented and discussed. The considered parameters are correlated with the compound structures. Structural increments for characteristic fragments of the molecule are calculated and use to predict BN and BS values.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 134-138 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Sulfur ; n-Octane adsorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary From the adsorption isotherms of n-octane on the surface of sulfur at 29.8°C and 40.6°C some thermodynamic functions were determined. On the basis of these data the structure of the adsorbed layer of n-octane is postulated. The molecular interactions and adsorption mechanism are also discussed. It is stated that both quasi-liquid and quasi-sold layers may be formed on the surface of sulfur depending on the surface coverage with n-octane.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 313-318 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention index ; Slope of log plot ; Homologous series ; Partition coefficient
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The slope of the n-alkane log plot dt′R/dnc (t′R=adjusted retention time; nc=carbon number) for a stationary phase can be used to obtain the retention index of an unidentified substance in a chromatogram containing only one peak with a known retention index, or to predict the retention time of a substance from that of a different homolog in the same series. It can also be used to translate retention indices into relative retention time, partition coefficient or specific retention volume. Published values of the slope are collected and critically evaluated. Equations are deduced that predict its approximate value at a specified temperature given the value at only one other temperature.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 393-396 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Separation of optical isomers ; Chirasil-Val capillary columns ; Amino acid esters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary D,L-amino acids were derivatized with (+), (±)-2-butanol or N-trifluoroacetyl-L-prolyl chloride (L-TPC) and then chromatographed. Four optical isomers were separated on a Chirasil-Val capillary column. By this method, the concentration of optical impurities arising from the commercial optically active reagents can be determined. The observed abnormal elution orders of enantiomeric amino acid esters may be caused by a selective intermolecular force.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Essential oils ; Evaporation rate ; Perfume composition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple method was developed for the determination of the evaporation rate of essential oils and perfumery composition using gas chromatography with temperature programming. The volatility of 19 essential oils and 17 perfumery composition was evaluated. The method is useful for different comparative measurements.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 598-602 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Capillary columns ; Steroid profiles
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Steroid conjugates are hydrolysed enzymatically using β-glucuronidase after extraction from urine using a solid phase extraction cartridge. After hydrolysis the free steroids are removed from the matrix, again utilising solid phase extraction. Derivatisation of the free hydroxyl groups using Hydrox-Sil AQ produces the respective TMS ethers which are extracted into hexane, in which solvent they are stable for many days. Capillary GC analysis with flame ionisation detection produces a profile of the steroids present in the sample. This technique is suitable for following changes in the urinary excretion profiles of patients undergoing investigation for a variety of steroid production-related diseases.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 609-612 
    ISSN: 1612-1112
    Keywords: Column liquid chromatography ; Gas chromatography ; Triglyceride composition of grapes ; Identification system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The triglyceride composition of the Tempranillo grape (Vitis vinifera) has been examined by a combination of HPLC and GLC. To identify the triglycerides, equations were applied relating log k′ with the molecular variables: equivalent carbon number, chain length and number of double bonds in each of the fatty acids in the glycerides. Ten triglycerides were found, the principal ones being trilinolein (35.75%), dilinoleyl-olein (21.03%) and dilinoleyl-palmitin (17.02%).
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 655-658 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Structure-retention relationships ; Connectivity indices, topological indices ; Alkenes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Retention indices of different alkenes are correlated with connectivity and topological parameters. The appropriate statistically valid relations hips are derived and discussed.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 735-736 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; α,ω-diiodoperfluoroalkanes ; Separation ; identification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The separation of α,ω-diiodoperfluoralkanes on a glass capillary column coated with OV-101 methylsilicone was investigated. Retention indices were determined at three temperatures (140, 150 and 160°C). The correlation between the retention indices and the boiling points of the investigated compounds was studied.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 731-734 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention Index (l) ; Temperature dependence of Retention Index
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A linear dependence of (T−T1)/[1(T)−1(T1)] on temperature (considering the retention index 1(T1) at temperature T1 as a standard value) is derived. Both ther retention index at an assigned temperature and the temperature dependence of the retention index can be calculated from retention data measured at two temperature-programing rates.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 26 (1988), S. 171-177 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; GC/MS analysis ; Polycyclic aromatic hydrocarbons ; Bituminous coal ; Brown coal ; Plant waxes ; Thermodesorption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Polycyclic aromatic hydrocarbons (PAH) today are ubiquitous detectable constituents of recent sediments. The compounds are adsorbed on particulate emissions and are thus transferred to the environment. To date the analysis of PAH in sediments, dust samples and plant material is based mainly on the application of solvent-extraction methods followed by liquid chromatography and/or gas chromatographic separation of the extracts. An alternative approach for the analysis of PAH in solid samples such as coal, sediments, dust samples and plant waxes is shown in this contribution. A commercially available device for the analysis of volatile compounds present in solid matter is connected on-line to a GC/MS system. The device enables the thermal desorption of hydrocarbons at a temperature of 320°C. Subsequently, the hydrocarbons trapped on the initial part of the capillary column are analyzed by GC/MS. The application of mass chromatography provides the possibility of detection and quantitation of PAH in complex mixtures even when they coelute with other compounds. The sample amount required varies between 1 and 10 mg depending on the hydrocarbon content.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 26 (1988), S. 229-233 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Glass capillaries ; Chirasil-Val ; Immobilisation ; Enantiomeric separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Immobilisation methods of the chiral silicone stationary phase Chirasil-L-Val have been studied. In addition to the standard techniques of radical-induced immobilisation with dicumyl peroxide and azo tert-butane, immobilisation was solely achieved by thermal treatment: conditioning at low flow-rates or under stop-flow conditions led to unexpectedly high immobilisation despite mild temperatures. The presence of water vapor in the carrier gas accelerated the immobilisation process. While up to 75% immobilisation was attainable with both ATB and thermal methods, immobilisation with DCUP did not exceed 50%, despite relatively high DCUP concentrations. Whilst all immobilisation methods were accompanied by varying degrees of racemisation at the chiral centre, it was possible to establish conditions that yielded a high immobilisation (in excess of 70%) with a negligible loss in enantiomeric selctivity. The immobilisation reactions also slightly affected the polarity of the stationary phase, reflected in a shift of the Kovats-Indices of amino acid derivatives and in the accompanying “Squalane-Effect”. With respect to immobilisation, racemisation and polarity shift, thermal immobilisation with water-saturated carrier gas proved to be the optimum method.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    ISSN: 1612-1112
    Keywords: Gas chromatography ; (S)-(+)-Naproxen ; Amino acid methyl esters ; Resolution of diasteroisomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A GC method has been elaborated for the separation of enantiomers of some amino acid methyl esters after derivatization with activated (S)-(+)-naproxen. Nine amino acid ester paris were completely resolvede in a single run on a fused silica capillary column.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 993-998 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; HPLC system ; Micropacked column ; Organic mobile phase ; UV detection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Retention behaviours of aromatic hydrocarbons were examined by using the vapour of an organic substance as the mobile phase and silica gel as the stationary phase. Gas chromatographic separation of aromatic hydrocarbons was demonstrated by using a system comprising a liquid chromatographic (LC) pump, a micropacked column for LC, a column oven and a UV detector.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Retention index ; Hydrocarbons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention of hydrocarbons present in the C5 pyrolysis fraction of gasolines on the stationary phases squalane and methylsilicone oil JXR at 30, 40 and 50°C was investigated by capillary gas chromatography. The unified retention indices of the hydrocarbons were also calculated on squalane. The retention indices obtained on these two phases were interrelated and the quantitative relationship with the structure of the solutes was studied. Equations based on the unified retention indices calculated on squalane and some selected structural elements of the solutes permit the calculation of their retention on methylsilicone with sufficient accuracy.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 589-592 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Hold-up time determination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary New versions are suggested for the gas hold-up time calculation in gas chromatography. The results are compared with those obtained by using other methods. The advantages of the suggested ways of calculation are pointed out.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 621-626 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Pre-column photolysis ; Halogenated hydrocarbons ; Identification of photolysis products ; Reaction mechanisms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Photodecomposition of chloro- and bromoderivatives of saturated, unsaturated and aromatic hydrocarbons has been studied under flow conditions using reaction gas chromatography. The photodegradation products were separated on a column coated with squalane and identified by comparing the measured retention data with those of standards and published retention indices, The results can be used to clarify the decomposition of such compounds.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 725-730 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Structure-retention correlation ; Kováts retention index ; Alkylaromatics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Relative retention data and Kováts retention indices were measured for several hydrocarbons (mainly for alkylbenzenes) on dinonylphtalate and polyethylenelycol 4000 stationary phase. Correlations were searched between these retention data and the following physical (boiling point, molrefraction, molvolume) and topological (connectiviity index and general index of molecular complexity) properties of solutes. The best fitting equations was choosen among more than 150 equations involving linear, quadratic, exponential, two variables linear and quadratic dependence of retention data and the properties mentioned as well as their inverses.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 817-821 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Water analysis ; Macroreticular polymeric adsorbent resins ; Herbicides
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A method is described for the determination of 3-phenyl-4-hydroxy-6-chloropyridazine in potable water. The method is based on isolation and enrichment by passing the water sample through a column of macroreticular polymeric adsorbent resin, concentration, derivatisation with pentafluorobenzoyl chloride and GC measurement with a N-specific detector. The individual experiments for establishing the working conditions, especially the adsorption characteristics of different types of resin, are described. The highest enrichment efficiency is obtained with the methacrylate-type resin XAD7. In field-sampling experiments a 10cm column yields 57% recovery at 100mLmin−1 flow rate, 0.3 ppb concentration level and 1 L sample volume. The method is completely documented; performance data are a detection limit of 0.07 μg L−1 and a mean recovery of 75% at the 0.3 ppb level.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Liquid crystals ; Thermodynamic properties
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Thermodynamic properties of 22 solutes at infinite dilution have been determined in the smectic, nematic and isotropic mesophases of 4,4′-bis(heptyloxy)azoxybenzone. The thermodynamic properties are discussed in relation to the solute-solvent (liquid crystal) interactions as conditioned by the degree of order in the liquid crystal.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Perhalogenated compounds ; Relative retentions ; Identification by interpolation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Separation of perhalogenated compounds resulting from thermolysis, photolysis or radiolysis of mixtures of halogens in carbon tetrachloride was carried out by programmed temperature gas chromatography. Plots of relative retentions (to CBr4) vs the number of bromine atoms present for known compounds of the general formula CxBryClz (x=1 and 2; y+z=4 or 6) gave three linear correlations (all with r〉0.99). These correlations permitted projections of the identities of reaction products for which no standards were available. These projections were later confirmed by CG-MS. *** DIRECT SUPPORT *** A0732166 00010
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    ISSN: 1612-1112
    Keywords: Gas chromatography ; On-line process analysis ; Injection of volatile compounds
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A modified on-line liquid injection technique with rotary valves for gas chromatography has been developed. Applications for the on-line analysis of 2-methylpropene, cyclohexene and 1-butene are described. All samples were loaded under pressure. The results obtained show excellent reproducibility with less than 0.1% relative standard deviation (r.s.d.; n=6) for the peak areas measured. The method is particularly advantageous for samples containing both gas and liquid ccomponents at one bar.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 87-90 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Free acids in cheese ; Tetramethylammonium hydroxide soaps ; Packed and capillary columns
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A rapid gas chromatographic method for the analysis of individual free fatty acids (FFA) in cheese has been developed. Lipds were extract from a cheese paste acidified with diethyl ether and tetramethylammonium hydroxide (TMAM) was used for converting the FFA to TMA-soaps, which are transformed to methyl esters in the chromatographic injector. The effect of lactic acid was determined. The reproducibility of the method was studied and the coefficient of variation for the total FFA was found to be 2.2%. Recovery of individual FFA was in the range 87 to 106%.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 453-454 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Reversed-flow technique ; Polymer activities ; Polymer interaction parameters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The reversed-flow, gas-chromatographic method for measuring activities and activity coefficients in binary liquid mixtures is now extended to the determination of activity coefficients of the solvent in polymer-solvent systems over the whole range of polymer concentration, as well as for the calculation of Flory-Huggins interaction parameters. The parameters found by the present method are compared with those determined by other techniques or calculated theoretically.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Glass capillary columns ; Bile acids ; Hexafluoroisopropyl esters
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A modified gas chromatographic glass capillary technique for determination of five major bile acids (Cholic acid: CA, Chenodeoxycholic acid: CDCA, Deoxycholic acid: DCA, Lithocholic acid: LCA and Ursodeoxycholic acid: UDCA) has been developed after preliminary extraction with XAD-2 resin. Enzymatic hydrolysis prevents the formation of interferring degradation products. Ether extraction with centrifugation eliminates water soluble interferring substances. Derivatization to hexafluorpropyl- instead of methyl esters results in better separation, shortens analysis time and prolongs the life span of the column.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 547-559 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Liquid column chromatography ; Process scale separations ; Review
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The relative merits of large scale gas chromatography (GC) and high performance liquid chromatography (HPLC) have not been reviewed for some considerable time. Although methodologies capable of manufacturing high efficiency (and hence cost effective) plant have existed for over a decade, commercial introduction has been remarkably slow. This has primarily been caused by confidentiality restrictions placed on equipment manufacturers, in turn severely limiting wide ranging applications data. These are necessary to raise potential end users confidence that both techniques offer viable large scale routes to separation and purification of mixtures as analysed by laboratory chromatographic methods. Considerable recent progress has been made with large scale HPLC plant, which has led to sufficient published data to make both technical and economic comparisons against GC possible.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 618-620 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Toluenesulfonic acid isomer distribution ; Ethyl toluenesulfonate isomers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A gas chromatographic method for the determination of isomeric distribution in toluenesulfonic acid samples is described. The acids are transformed into the corresponding ethyl esters by reaction with triethyl orthoformate in toluene. The reaction mixture can be injected, without further purification, into the gas chromatograph. The separation is best performed on columns containing OV-210 or polyphenyl ether (6 rings) as the stationary phase.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 25 (1988), S. 691-693 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Al, Cr, Co and Fe acetylacetonates ; Capillary column separation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary The retention and resolution of simple mixture of Al(III), Cr(III), Co(III), and Fe(III) acetylacetonates were investigated on capillary columns coated with methyl and methyl phenyl silicones (OV-1 or OV-17) used as the stationary phase, at different column temperatures and carrier gas flow rates. Successful elution and good resolution were obtained only for the Al(III) and Cr(III) complexes, both under isothermal and programmed-temperature conditions; better resolution was observed on the column coated with OV 17.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 26 (1988), S. 300-304 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Column liquid chromatography ; Polycyclic aromatic hydrocarbons ; Phenolic compounds ; Air pollution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary An improved procedure for the determination of the less volatile air pollutants of recycled closed atmospheres by activated carbon-Soxhlet extraction is proposed. After total treatment of desorbate, PAH determination is then accomplished by RP-HPLC using both adsorptiometric and fluorimetric UV detection; phenolic compounds are determined by GC-MS. This technique is suitable for very low levels of PAH and phenolic compounds.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 26 (1988), S. 34-36 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Gas analysis in halogen lamps ; Sampling device
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A new type of gas sampling device was constructed to improve the analysis of the gas in halogen lamps. Low levels of gases such as O2, CH4, C2H4 and CH3Br could be determined by the techniques worked out.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Electronic Resource
    Electronic Resource
    Springer
    Chromatographia 26 (1988), S. 413-416 
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Gas analysis in incandescent lamps ; Gas chromatographic determination of O2 impurity in argon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A sensitive GC method was developed to analyse O2 (∼10–400ppm) in argon, by using Ar as carrier gas. A sampling method was developed for lamp analysis, and the O2 impurity content in the gas filling of incandescent lamps was measured. The results of the GC and MS measurements were in good agreement.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Electronic Resource
    Electronic Resource
    Springer
    Journal of chemical ecology 14 (1988), S. 87-94 
    ISSN: 1573-1561
    Keywords: Pheromone ; correlation ; kinship ; Dufour's gland ; social bee ; Lasioglossum zephyrum ; Hymenoptera ; Halictidae ; lactones
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Both males and females of the primitively eusocial beeLasioglossum zephyrum can distinguish among female conspecifics with regard to genealogical relationship. Closely related females covary with respect to Dufour's gland pheromone products which are believed to function in individual or kin recognition. This is the first report of a population-wide parallel between similarity of communicative glandular product and genetic similarity.
    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...