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  • American Institute of Physics  (18)
  • Springer  (15)
  • American Physical Society  (5)
  • Oxford University Press  (3)
  • American Chemical Society (ACS)
  • Copernicus
  • 1990-1994  (41)
  • 1
    ISSN: 1570-7458
    Schlagwort(e): Biocontrol ; sterilization ; mass release
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Journal of comparative physiology 174 (1994), S. 581-592 
    ISSN: 1432-1351
    Schlagwort(e): Honey bee ; Sting response ; Motor control ; Ventral nerve cord ; Maturation ; Caste
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Stinging behavior has been extensively studied in honey bees at the level of the individual, that is, in terms of stimuli that release stinging in adult bees, and in terms of integration of individual behavior into colony defense. Yet very little is known about the physiological basis for this behavior. Using an isolated abdominal preparation factors that influence peripheral control of the sting extension response are analyzed. Results show that: 1. Electromyogram activity released by severing the ventral nerve cord changed during the first few days of adult life but not later. Abdomens from older bees (nurses, guards, foragers) showed significantly higher EMG activity than newly emerged or 24 h-old bees. 2. The reflex “matured” over 5–7 days after emergence as an adult. 3. Younger bees (≤24h) had a lower threshold for initiating sting extension than older bees. However, the threshold for initiating the full sting response, i.e., extension and venom pumping, did not differ due to age. 4. Caste status was not correlated to any of the parameters of sting extension, indicating that any effect of caste on stinging behavior must arise in more anterior ganglia and/or in the brain.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    ISSN: 1432-2048
    Schlagwort(e): Phosphofructokinase ; Solanum (phosphofructokinase) ; Sugar accumulation ; Temperature and phosphofructokinase activity ; Tuber (cold-induced sweeting)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The aim of this work was to compare the coldlability of phosphofructokinase (EC 2.7.1.11) from tubers of potato cultivars (cvs.) known to differ in their propensity to accumulate sugars at low temperature. When stored at 4°C for six weeks, the sugar content of tubers ofSolanum tuberosum L. cv. Record doubled whereas the amount of sugar in tubers of cv. Brodick and an advanced breeding clone (13676) decreased slightly. Tubers from each line contained four forms of phophofructokinase. Over the range 12°–16°C the temperature coefficients of the four forms of phosphofructokinase from cvs. Record and Brodick were similar. In cv. Record the temperature coefficients of three of the enzyme forms were significantly higher at 2°–6°C than at 12°–16°C, whereas those from cv. Brodick were unchanged. These results are consistent with the proposal that inactivation of phosphofructokinase at low temperature results in the accumulation of hexose phosphates leading to increased sucrose synthesis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    ISSN: 1573-5028
    Schlagwort(e): β-glucuronidase (GUS) (β-D-glucuronoside glucuronosohydrolase ; E.C.3.2.1.31) ; patatin ; potato cultivar promoter ; transgenic expression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Patatin is a family of glycoproteins that contributes about 40% of the total soluble protein in tubers of potato (Solanum tuberosum L.). The protein is encoded by a multigene family of 50–70 genes which have been divided into classes I and II on the basis of sequence homology. The promoters of two class I genes, PS20 and PS3/27, were transcriptionally fused to β-glucuronidase and transformed into the potato cultivars Désirée and Maris Bard. Examination of the expression levels in large populations of microtubers indicated that the PS20 promoter produced β-glucuronidase activities 5-fold lower in Désirée than Maris Bard whereas the PS3/27 promoter showed similar levels in both cultivars. Furthermore, the relative expression levels from the two promoters were reversed in the two cultivars. The β-glucuronidase enzyme activity was correlated with the mRNA level but not the copy number of the introduced gene. The implications for the use of patatin promoters in the genetic modification of tubers is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1432-2048
    Schlagwort(e): Glycolysis (regulation) ; 6-Phosphofructokinase ; Solanum (respiration) ; Transgenic plant (potato)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The aim of this work was to discover whether genetic manipulation of 6-phosphofructokinase [EC 2.7.1.11; PFK(ATP)] influenced the rate of respiration of tuber tissue of Solanum tuberosum L. Transgenic plants were produced that contained the coding sequence of the Escherichia coli pfkA gene linked to a patatin promoter. Expression of this chimaeric gene in tubers resulted in a 14to 21-fold increase in the maximum catalytic activity of PFK(ATP) without affecting the activities of the other glycolytic enzymes. Tubers, and ‘aged’ disks of tuber tissue, from transformed plants showed no more than a 30% fall in the content of hexose 6-monophosphates; the other intermediates of glycolysis increased threeto eightfold. Fructose-2,6-bisphosphate was barely detectable in aged disks of transformed tubers. The relative rates of 14CO2 production from [1-14C]-and [6-14C]-glucose supplied to disks of transformed and control tubers were similar. Oxygen uptake and CO2 production by aged disks of transformed tubers did not differ significantly from those from control tubers. The same was true of CO2 production, in air, and in nitrogen, for tuber tissue. It is concluded that PFK(ATP) does not dominate the control of respiration in potato tubers.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    ISSN: 1432-0878
    Schlagwort(e): Neuroendocrine cells ; Intestine ; Chromogranin ; Serotonin ; Regulatory peptides ; Immunocytochemistry ; Podarcis hispanica (Reptilia, Lacertilia)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Numerous endocrine cells can be observed in the gut of the lizard Podarcis hispanica after application of the Grimelius silver nitrate technique. The argyrophilic endocrine cells are usually tall and thin in the small intestine but short, basal, and round in the large intestine. Eleven types of immunoreactive endocrine cells have been identified by immunocytochemical methods. Numerous serotonin-, caerulein/gastrin/cholecystokinin octapeptide-and peptide tyrosine-tyrosine-immunoreactive cells; a moderate number of pancreatic polypeptide-, neurotensin-, somatostatin-, glucagon-like peptide-1-and glucagon-immunoreactive cells, and few cholecystokinin N-terminal-and bombesin-immunoreactive cells were found in the epithelium of the small intestine. Coexistence of glucagon with GLP-1 or PP/PYY has been observed in some cells. In the large intestine a small number of serotonin-, peptide tyrosine-tyrosine-, pancreatic polypeptide-, neurotensin-, somatostatin-and glucagon-like peptide-1-immunoreactive cells were detected. Vasoactive intestinal peptide immunoreactivity was found in nerve fibers of the muscular layer. Substance P-immunoreactive nerve fibers were detected in lamina propria, submucosa and muscular layer. Chromogranin A-immunoreactive cells were observed throughout the intestine, although in lower numbers than argyrophilic cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 273 (1993), S. 89-95 
    ISSN: 1432-0878
    Schlagwort(e): Endocrine cells, pulmonary ; Regulatory peptides ; Lung ; Immunocytochemistry ; Domestic fowl ; Domestic pigeon
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract the presence of endocrine cells and nerves in the lung of 2 avian species (Gallus gallus and Columba livia domestica) has been studied by peroxidase-antiper-oxidase (PAP) and avidin-biotin complex (ABC) immunocytochemical methods at the light-microscopic level. Two immunoreactive cell-types have been identified in the epithelium of the primary and secondary bronchi of chick lung: serotonin- and bombesin-immunoreactive cells; and 3 cell-types, namely, serotonin-, bombesin- and CGRP-(calcitonin gene related peptide) immunoreactive cells, have been located in the bronchial epithelium of pigeon lung. Co-localization of 2 different immunoreactivities within the same cell has not been detected. VIP-immunoreactive nerves have been observed in different locations in chick lung.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Scientometrics 30 (1994), S. 505-509 
    ISSN: 1588-2861
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Buch- und Bibliothekswesen, Informationswissenschaft , Wissenschaftskunde und Wissenschaftsorganisation, Hochschul- und Universitätswesen, Museumswissenschaft
    Notizen: Conclusion As a mathematician working in the general field of informetrics, I would respond to G & S by pleading to all those who take any interest or responsibility in the development of the discipline that, in judging the value of any mathematical work, we must ensure not just its integrity but its ease of applicability for the practitioners —i.e. those who must actually use our work (unless it is all merely an academic exercise).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Scientometrics 21 (1991), S. 181-194 
    ISSN: 1588-2861
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Buch- und Bibliothekswesen, Informationswissenschaft , Wissenschaftskunde und Wissenschaftsorganisation, Hochschul- und Universitätswesen, Museumswissenschaft
    Notizen: Abstract It is pointed out that the so-called “Bradford distribution” derived by Leimkuhler is more properly viewed as the theoretical form of a variant of the Lorenz curve. The equation of this Leimkuhler curve allows an easy calculation of the Gini coefficient of concentration which can be compared with empirical values.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
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