ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
Filter
  • Rat  (286)
  • Immunocytochemistry  (203)
  • growth
  • stability
  • Springer  (656)
  • Annapolis, MD
  • Austin, TX
  • Kiel: Kiel Institute for the World Economy (IfW)
  • MDPI Publishing
  • 1985-1989  (656)
Sammlung
Schlagwörter
Verlag/Herausgeber
Erscheinungszeitraum
Jahr
  • 1
    ISSN: 1435-604X
    Schlagwort(e): Brain tumour ; Rat ; Detection ; Fluorescence ; Laser ; Haematoporphyrin derivative
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin , Physik , Technik allgemein
    Notizen: Abstract Laser-induced fluorescence has been used for the identification of brain tumours in rats, which have been previously given tumour-seeking haematoporphyrin derivative. A pulsed nitrogen laser (λ=337 nm) was used in conjunction with an optical multichannel analyzer. For both inoculated RG-2 and TCVC rat-brain-tumour models, the blue autofluorescence was strongly reduced in the tumour compared with normal brain tissue, and at the same time the characteristic red-drug signal increased. The contrast between tumour and normal tissue was strongly enhanced by forming the ratio between the two signals. Implications for possible improvement of tumour delineation in brain tumour surgery are discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Entomologia experimentalis et applicata 53 (1989), S. 257-265 
    ISSN: 1570-7458
    Schlagwort(e): Antifeedant ; insecticide ; bisabolangelone ; analog ; feeding ; growth ; molting ; mortality ; sesquiterpenoid ; development ; phago-stimulant ; Pieris brassicae L. ; Lepidoptera ; Pieridae ; Angelica silvestris L. ; Umbelliferae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Bisabolangelone und drei Analoge wurden unter Laboratoriumsbedingungen auf ihre frasshemmende Wirkung in Raupen von Pieris brassicae L. (Lepidoptera: Pieridae) geprüft. Die Resultate von Zweifach-Wahlversuchen zeigten, dass sowohl die frasshemmende als auch die insektizide Wirkung von Bisabolangelone in den Analogen stark reduziert ist oder ganz verloren ging. Weitere Untersuchungen mit niedrigen Bisabolangelone-Dosen zeigten, dass das Fehlen von wohlschmeckender Nahrung zu einer drastischen Reduktion der Nahrungsaufnahme und des Wachstums der Raupen sowie zur Verhinderung der Häutung und zu hoher Mortalität führt. Deformationen, wie sie von bisabolangelone-behandelten Vorratsschädlingen gemeldet wurden, konnten bei P. brassicae nicht beobachtet werden.
    Notizen: Abstract Bisabolangelone and three analogs were assayed, under laboratory conditions, for their antifeedant activity against Pieris brassicae L. (Lepidoptera: Pieridae) larvae. The results of dual-choice studies revealed that the potent antifeedant activity of bisabolangelone is greatly reduced or lost in the analogs. Insecticidal activity observed in the former was not detected either. Further studies using the lower rates of bisabolangelone showed that the absence of a preferable food resulted in a drastic reduction in feeding and growth, and produced high mortality and inhibition of molting. No developmental deformities reported in stored product insects treated with bisabolangelone were observed in P. brassicae during our studies.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Journal of dynamics and differential equations 1 (1989), S. 269-298 
    ISSN: 1572-9222
    Schlagwort(e): Geometric mechanics ; reduction ; stability ; chaos ; rigid body dynamics ; periodic orbits ; 58F
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract We give a complete bifurcation and stability analysis for the relative equilibria of the dynamics of three coupled planar rigid bodies. We also use the equivariant Weinstein-Moser theorem to show the existence of two periodic orbits distinguished by symmetry type near the stable equilibrium. Finally we prove that the dynamics is chaotic in the sense of Poincaré-Birkhoff-Smale horseshoes using the version of Melnikov's method suitable for systems with symmetry due to Holmes and Marsden.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Journal of dynamics and differential equations 1 (1989), S. 299-325 
    ISSN: 1572-9222
    Schlagwort(e): Commodity markets ; time delays ; stability ; Hopf bifurcation ; 34K15 ; 45J05 ; 90A16
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract A model for the dynamics of price adjustment in a single commodity market is developed. Nonlinearities in both supply and demand functions are considered explicitly, as are delays due to production lags and storage policies, to yield a nonlinear integrodifferential equation. Conditions for the local stability of the equilibrium price are derived in terms of the elasticities of supply and demand, the supply and demand relaxation times, and the equilibrium production-storage delay. The destabilizing effect of consumer memory on the equilibrium price is analyzed, and the ensuing Hopf bifurcations are described.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Celestial mechanics and dynamical astronomy 47 (1989), S. 333-359 
    ISSN: 1572-9478
    Schlagwort(e): symplectic maps ; stability ; normal forms
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We prove that non resonant isochronous symplectic maps in a neighborhood of an elliptic fixed point are stable for exponentially long times with the inverse of the distance from the fixed point. In the proof we make use of the majorant series method together with an idea for optimizing remainder estimates first applied to Hamiltonian problems by Nekhoroshev.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 6
    ISSN: 1432-1432
    Schlagwort(e): Carcinoembryonic antigen ; Evolution ; Gene family ; Human ; Rat ; Synonymous substitutions ; Silent molecular clock ; Evolutionary trees
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Various rodent and primate DNAs exhibit a stronger intra- than interspecies cross-hybridization with probes derived from the N-terminal domain exons of human and rat carcinoembryonic antigen (CEA)-like genes. Southern analyses also reveal that the human and rat CEA gene families are of similar complexity. We counted at least 10 different genes per human haploid genome. In the rat, approximately seven to nine different N-terminal domain exons that presumably represent different genes appear to be present. We were able to assign the corresponding genomic restriction endonuclease fragments to already isolated CEA gene family members of both human and rat. Highly similar subgroups, as found within the human CEA gene family, seem to be absent from the rat genome. Hybridization with an intron probe from the human nonspecific cross-reacting antigen (NCA) gene and analysis of DNA sequence data indicate the conservation of noncoding regions among CEA-like genes within primates, implicating that whole gene units may have been duplicated. With the help of a computer program and by calculating the rate of synonymous substitutions, evolutionary trees have been derived. From this, we propose that an independent parallel evolution, leading to different CEA gene families, must have taken place in, at least, the primate and rodent orders.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Journal of statistical physics 54 (1989), S. 1427-1427 
    ISSN: 1572-9613
    Schlagwort(e): Kink propagation ; kink width ; characteristic functions ; stability ; continuum of modes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We consider the propagation of kinks in an elastic chain in a bistable or multistable potential under the action of a driving force [M. Büttiker and H. Thomas,Phys. Rev. A 37:235 (1988)]. Each element of the chain is subject to a damping force proportional to its velocity. We show that both the propagation velocity of the kinks as a function of the driving field, and the kink width as a function of propagation velocity, are determined by characteristic functions which depend only on the form of the potential. These functions can be found by considering a single particle moving in the upside-down potential of the chain. The general properties of these functions are studied and illustrated by several examples. The stability of these driven kinks is discussed. Interestingly, we find in addition to the expected discrete localized eigenmodes a two-dimensional continuum of oscillatory modes with a localized envelope.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Journal of statistical physics 55 (1989), S. 141-156 
    ISSN: 1572-9613
    Schlagwort(e): Kosterlitz-Thouless ; Coulomb gas ; hierarchical model ; renormalization group ; screening ; stability ; bifurcation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract A hierarchical version of two-dimensional lattice Coulomb gases is investigated. Forβ〉β c=8π there is a locally stable line of fixed points for the renormalization group (“block charges”) transformations. For $$\beta 〉 \bar \beta _c (\beta _c \leqslant \bar \beta _c \leqslant \tfrac{3}{2}\pi \beta _c )$$ , these fixed points are globally stable. As a consequence we show that there is no screening of external charges for any activity if $$\beta 〉 \bar \beta _c $$ . Atβ c a supercritical bifurcation takes place and we investigate the behavior of the model forβ≲β c to show a weak form of screening.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Landscape ecology 3 (1989), S. 43-51 
    ISSN: 1572-9761
    Schlagwort(e): Czechoslovakia ; CSSR ; Slovakia ; ecological model ; planning ; landscape management ; stability ; disturbance
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Development of the general ecological model (EM) of the CSSR has been included in the state program for environmental policy - the Ecoprogramme of the CSSR — at a scale of 1:1 000 000 for the entire Czechoslovak territory and at a scale of 1:500 000 for the Czech Socialist Republic (CSR) and the Slovak Socialist Republic (SSR). The objective of the first EM stage was to make a survey of spatial differentiation of the major ecological problems of the country. The EM consists of four parts, three analytical and one synthetic. These parts are: a. The ecological state (value) of the current spatial structure of the landscape. b. Ecological stress factors in the landscape. c. Protection of nature and natural resources. From the spatial synthesis of these three groups (from their spatial encounters), the following synthetic group of conditions was obtained: d. Regional ecological problems, a system of ecologically stable areas, environmental stress factors and factors endangering the ecological stability of the landscape, the natural resources and the human environment.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Acta mechanica solida Sinica 2 (1989), S. 285-294 
    ISSN: 0894-9166
    Schlagwort(e): Liapunov function ; stability ; discrete time system ; decision matrix
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Physik
    Notizen: Abstract The purpose of this paper is to present a new method for constructing Liapunov function and determining the stability of discrete time systems with a computer on the basis of the similarity transformation theory by directly applying the system matrix of the system under discussion instead of solving the discrete Liapunov's matrix equation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 11
    Digitale Medien
    Digitale Medien
    Springer
    Pure and applied geophysics 130 (1989), S. 743-749 
    ISSN: 1420-9136
    Schlagwort(e): Dynamic systems ; multiple equilibrium ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Geologie und Paläontologie , Physik
    Notizen: Abstract A set of ordinary differential equations describing a mechanical system subject to forcing and dissipation is considered. A topological argument is employed to show that if all time-dependent solutions of the governing equations are bounded, the equations admitN steady solutions, whereN is a positive odd integer and where at least (N−1)/2 of the steady solutions are unstable. The results are discussed in the context of atmospheric flows, and it is shown that truncated forms of the quasigeostrophic equations of dynamic meteorology and of Budyko-Sellers climate models satisfy the hypotheses of the theorem.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 12
    Digitale Medien
    Digitale Medien
    Springer
    Aquatic sciences 51 (1989), S. 296-305 
    ISSN: 1420-9055
    Schlagwort(e): Arctic char ; growth ; maturation ; reoligotrophication ; Lake Walenstadt
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Within one decade the yield in arctic char fishery of Lake Walenstadt (Switzerland) has dropped from 1.7 kg · ha−1 to 0.7 kg · ha−1. In the same period growth decreased by about 15%. The fish considered as “degenerated dwarfed chars” by fishermen are supposed to mature in very young ages. The change of the growth pattern can be related to reoligotrophication of the lake and impoverishments of the food source. Compared to other arctic char populations in Switzerland maturation takes place at least one year later.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 13
    ISSN: 1432-1351
    Schlagwort(e): Rat ; Melatonin ; Circadian rhythm ; 5-hydroxytryptophan
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The rhythm in melatonin production in the rat is driven by a circadian rhythm in the pineal N-acetyltransferase (NAT) activity. Rats adapted to an artificial lighting regime of 12 h of light and 12 h of darkness per day were exposed to an 8-h advance of the light-dark regime accomplished by the shortening of one dark period; the effect of melatonin, triazolam and fluoxetine, together with 5-hydroxytryptophan, on the reentrainment of the NAT rhythm was studied. In control rats, the NAT rhythm was abolished during the first 3 cycles following the advance shift. It reappeared during the 4th cycle; however, the phase relationship between the evening rise in activity and the morning decline was still compressed. Melatonin accelerated the NAT rhythm reentrainment. In rats treated chronically with melatonin at the new dark onset, the rhythm had already reappeared during the 3rd cycle, in the middle of the advanced night, and during the 4th cycle, the phase relationship between the evening onset and the morning decline of the NAT activity was the same as before the advance shift. In rats treated chronically with melatonin at the old dark onset or in those treated with melatonin 8 h, 5 h and 2 h after the new dark onset during the 1st, 2nd and 3rd cycle, respectively, following the advance shift, the NAT rhythm reappeared during the 3rd cycle as well but in the last third of the advanced night only. Neither triazolam nor fluoxetine together with 5-hydroxytryptophan administered around the new dark onset facilitated NAT rhythm reentrainment after the 8-h advance of the light-dark cycle.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 14
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 258 (1989), S. 119-124 
    ISSN: 1432-0878
    Schlagwort(e): Development, ontogenetic ; Immunocytochemistry ; Monoclonal antibodies ; Mucosa ; Lymphoid organs ; Domestic fowl
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The postnatal development of chicken mucosa-associated lymphoid tissues of the eyes, lungs, and intestines were investigated with monoclonal antibodies specific for either all leucocytes, B lymphocytes, mononuclear phagocytes, IgM, IgG, or IgA. Attention has been paid to the relation of lymphoid infiltrates with their surrounding mucosae, the segregation into B-cell and T-cell areas, development of germinal centers, and secretory immunoglobulins. Abudant secretory IgM and IgA was detected in the epithelium of the Harderian glands in the orbits, even though they lacked large leucocyte infiltrates with germinal centers. Lymphoid tissues in the mucosae of lungs and intestines developed separate B-cell and T-cell areas. The proventriculus, Meckel's diverticulum, and Peyer's patches generally contained germinal centers from 12 weeks of age on. Because chickens as young as 2 weeks old had germinal centers in bronchus-associated lymphoid tissue and cecal tonsils, these areas were probably highly stimulated by antigens. Isotype-specific monoclonal antibodies were used to detect IgM-, IgG-, and IgA-bearing follicular cells in the same germinal center.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 15
    ISSN: 1432-0878
    Schlagwort(e): Insect AKH/RPCH ; Neurohormones ; Cam-HrTH-II ; Lom-AKH-I ; Immunocytochemistry ; Carausius morosus, Sarcophaga bullata (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary A polyclonal antiserum was prepared against an N-terminal modified Cam-HrTH-II (Leu-Asn-Phe-...), one of the members of the large AKH/RPCH peptide family, first isolated from Carausius morosus. The localisation of this peptide was performed by means of immunocytochemical methods in the brain and corpora cardiaca-corpora allata complex of the stick insect, Carausius morosus and the grey fleshfly, Sarcophaga bullata. The distribution patterns of molecules reactive to the Cam-HrTH-II and the LomAKH-I antisera in both insect species were compared. In Carausius, both antisera reacted in the same cell bodies. In Sarcophaga, some neurons were stained by both, others only by one of the two antisera. By combining two different antisera, we demonstrated that there are no Lom-AKH-I-like molecules present in Carausius and that there must occur at least three different AKH-like molecules in the brain of Sarcophaga. One is similar to Cam-HrTH-II, the second to Lom-AKH-I and the third is an AKH/RPCH-like peptide, different from Lom-AKH-I and Cam-HrTH-II.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 16
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 258 (1989), S. 1-24 
    ISSN: 1432-0878
    Schlagwort(e): Serotonin ; Immunocytochemistry ; Insect nervous system ; Protocerebrum ; Suboesophageal ganglion ; Manduca sexta (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Serotonin-immunoreactive neurons in the median protocerebrum and suboesophageal ganglion of the sphinx moth Manduca sexta were individually reconstructed. Serotonin immunoreactivity was detected in 19–20 bilaterally symmetrical pairs of interneurons in the midbrain and 10 pairs in the suboesophageal ganglion. These neurons were also immunoreactive with antisera against DOPA decarboxylase. All major neuropil regions except the protocerebral bridge are innervated by these neurons. In addition, efferent cells are serotonin-immunoreactive in the frontal ganglion (5 neurons) and the suboesophageal ganglion (2 pairs of neurons). The latter cells probably give rise to an extensive network of immunoreactive terminals on the surface of the suboesophageal ganglion and suboesophageal nerves. Most of the serotonin-immunoreactive neurons show a gradient in the intensity of immunoreactive staining, suggesting low levels of serotonin in cell bodies and dendritic arbors and highest concentrations in axonal terminals. Serotonin-immunoreactive cells often occur in pairs with similar morphological features. With one exception, all serotonin-immunoreactive neurons have bilateral projections with at least some arborizations in identical neuropil areas in both hemispheres. The morphology of several neurons suggests that they are part of neuronal feedback circuits. The similarity in the arborization patterns of serotonin-immunoreactive neurons raises the possibility that their outgrowing neurites experienced similar forces during embryonic development. The morphological similarities further suggest that serotonin-immunoreactive interneurons in the midbrain and suboesophageal ganglion share physiological characteristics.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 17
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 258 (1989), S. 101-109 
    ISSN: 1432-0878
    Schlagwort(e): Serotonin ; Immunocytochemistry ; Subesophageal ganglion ; Neurohemal organs ; Manduca sexta (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Serotonin-immunoreactivity is mapped in wholemounts and slices of the suboesophageal ganglion (SOG) of larval Manduca sexta by means of immunocytochemistry. An extensive meshwork of serotonin-immunoreactive nerve fibres on some peripheral nerves of the SOG has been demonstrated. This meshwork appears to belong to a serotonergic neurohemal system, probably supplied by two pairs of bilateral serotonin-immunoreactive neurons with big cell bodies on the dorsal side near the midline in the mandibular neuromere. Intracellular recording and staining revealed their physiology and morphology. These neurons produce long lasting (50 msec) action potentials, which suggest that they are neurosecretory cells. Two pairs of bilateral serotonin-immunoreactive interneurons similar to those of other insects are stained in the labial and maxillar neuromeres, but not in the mandibular neuromere. Their ventrolaterally located cell bodies project through a ventral commissure into the contralateral hemiganglion and then cross back again through a dorsal commissure. The axons project into the contralateral circumoesophageal connective.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 18
    ISSN: 1432-0878
    Schlagwort(e): Na+, K+-ATPase ; Immunocytochemistry ; Kidney ; Salivary glands ; Transport ; Rat (Sprague-Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary An antibody to the 96 kD α-subunit of the Na+, K+ -ATPase from Bufo marinus has been used in immunostaining rat kidney and salivary glands. Intense staining was observed on basolateral membranes of distal tubules of the kidney and striated ducts of the three major salivary glands. Less intense staining was seen on the basolateral membranes of parotid acinar cells, but no staining was seen on the acinar cells of submandibular or sublingual glands. These sites of staining have been shown, by other methods, to posses substantial Na+, K+ -ATPase, indicating that the antibody recognizes antigenic determinants of the sodium pump highly conserved in the course of evolution. In addition, staining with this antibody was observed at the apical region of cells of the proximal straight tubule and of the papillary collecting duct in the kidney. Absorption studies suggest that the apical antigenic determinants are the same or closely related to each other but are distinct from basolateral antigenic determinants.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 19
    ISSN: 1432-0878
    Schlagwort(e): Met-enkephalin-Arg6-Phe7 ; Met-enkephalin-Arg6-Gly7-Leu8 ; Immunocytochemistry ; Neuropeptides ; Co-existence of peptides ; Neurosecretory cells, insects ; Blowfly, Calliphora vomitoria (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Neuronal pathways immunoreactive to antisera against the extended-enkephalins, Met-enkephalin-Arg6-Phe7 (Met-7) and Met-enkephalin-Arg6-Gly7-Leu8 (Met-8), have been identified in the brain of the blowfly Calliphora vomitoria. Co-localisation with other enkephalins in certain neurons suggests that a precursor similar to preproenkephalin A exists in insects and that differential enzymatic processing occurs as in vertebrates. Co-localisations of the extended-enkephalin-like peptides with other vertebrate-type peptides, including cholecystokinin and pancreatic polypeptide, also occur. The enkephalinergic pathways are specific, comprising a few groups of highly characteristic neurons and areas of neuropil. Of special interest is the finding that parts of the antennal chemosensory and the optic lobe visual systems contain Met-8 immunoreactive neurons. Within the median neurosecretory cell groups, some of the giant neurons show immunoreactivity to Met-8 and others to both Met-8 and Met-7. Fibres from these cells project to the corpus cardiacum and also to the suboesophageal ganglion, where arborisations occur in the tritocerebral neuropil. Co-localisation studies of these cells have shown that at certain terminals, one particular type of peptide is the dominant neuroregulator, whilst at other terminals, within the same cell, a different co-synthesised peptide predominates. Several groups of lateral neurosecretory cells show clearly defined enkephalinergic pathways, most of which have connections with the central body. The complex patterns of immunoreactivity seen in terminals in the different parts of the central body, suggest an important role for the enkephalin-like peptides in the integration of multimodal sensory inputs. The physiological functions of the extended-enkephalin-like peptides in the brain of Calliphora is still unknown, but the anatomical evidence suggests they may have a role similar to that in mammals, where they are thought to control aspects of feeding behaviour.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 20
    ISSN: 1432-0878
    Schlagwort(e): Gut hormones ; Insulin ; Bombesin ; Immunocytochemistry ; Pancreatic polypeptide ; Cholecystokinin (CCK) ; Gastrin ; Schistocerca gregaria (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The endocrine cells of the midgut epithelium of the desert locust are found dispersed among the digestive cells and are similar to those of the vertebrate gut. According to their reactivity to silver impregnation techniques and the ultrastructural features of the secretory granules (shape, electron-density, size, and structure) 10 types of endocrine cell have been identified, of which seven are located in the main segment of the midgut or in the enteric caeca, and the other three seem to be present only in the ampullae through which the Malpighian tubules drain into the gut. The endocrine cells have a slender cytoplasmic process that reaches the gut lumen, a feature that supports the receptosecretory nature postulated for this cellular type in insects as well as vertebrates. Antisera directed against mammalian gastrin, CCK, insulin, pancreatic polypeptide and bombesin reacted with some of the endocrine cells. This is the first time that insulin- and bombesin-like immunoreactive cells have been described in the midgut of an insect.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 21
    ISSN: 1432-0878
    Schlagwort(e): Somatotropes, growth hormone cells ; Immunocytochemistry ; Growth hormone (GH) ; Receptors, membrane ; Somatostatin (SRIF) ; Growth hormone-releasing hormone (GRH) ; Rat (Han: WIST)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The synthetic peptides somatostatin (SRIF) and growth hormone-releasing hormone (GRH) were coupled directly to colloidal gold of different particle sizes. Both conjugates were biologically active in displacing the corresponding radiolabeled hormones from high affinity binding sites in pituitary membranes. Release of growth hormone (GH) from cultured anterior pituitary cells was modulated by both conjugates alone or in combination. Ultrastructural studies were performed with cells incubated at 4° C (2 h) and 37° C (2 min-2 h) with one of the labeled peptides or their combination. Somatotropes were identified by immunostaining with anti-rGH followed by protein A-ferritin, thus obtaining a triple labeling. Both hormone conjugates were internalized in different vesicles in the beginning but accumulated during longer incubation times in the same compartment. The secretory vesicles and the nucleus were not labeled by any hormone conjugate. In contrast to SRIF-gold, the uptake of GRH-gold conjugate decreased with longer incubation times. This effect could be neutralized by simulatenous incubation of the somatotropes with both regulating hormones. Hence, whereas the binding and internalization of SRIF by somatotropes do not seem to be influenced by GRH, the corresponding processes for GRH are stimulated by the presence of SRIF.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 22
    ISSN: 1432-0878
    Schlagwort(e): Gills ; Indoleamines ; Immunocytochemistry ; Autonomic innervation ; Salmo gairdneri R. ; Perca fluviatilis L. ; Micropterus dolomieui (Lacépède) ; Anguilla anguilla L. ; Ictalurus melas Rafinesque (Teleostei) ; Acipenser baeri L. (Chondrostei)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Antibodies against serotonin and 5-methoxytryptamine reveal indolaminergic neurons innervating the proximal part of the efferent arterial vasculature, the filament epithelia, the central venous sinus, and certain other serotonergic cells of the teleost gill filament. In the same area, acetylcholinesterase-positive and indoleaminergic neurons have already been described. We propose that these populations of neurons belong to a single neuronal type but express different agents. Our current results support this idea; in particular, they point to the presence of a single type of serotonin-containing nerve terminal, impinging on vascular smooth muscle. These results are in agreement with physiological data showing (i) the existence of non-cholinergic (atropine-resistant) vasoconstriction of the gill vasculature after nerve stimulation, and (ii) a potent vasoconstrictory action of infused serotonin. In addition, the above-mentioned serotonergic neurons have synaptic contacts with catecholaminergic nerve fibers, suggesting the existence of a modulatory relationship between the sympathetic and the cranial autonomic nerves supplying the teleost gill. Finally, these neurons show morphological relationships with a previously undescribed type of branchialserotonergic cell. The role of the parasympathetic nerve plexus of the teleost gill filament in the control of respiration and ionoregulation is discussed.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 23
    ISSN: 1432-0878
    Schlagwort(e): Subcommissural organ ; Secretory activity, neural control ; Transplantation ; Long-spacing collagen ; Immunocytochemistry ; Molecular markers (neuronal, glial) ; Electron microscopy ; Rat (Sprague-Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary There is increasing evidence that, in the rat, a serotonin-mediated neural input may have an inhibitory influence on the secretory activity of the subcommissural organ (SCO). In the present investigation the rat SCO was studied 7, 30 and 90 days after transplantation under the kidney capsule, an area devoid of local serotonin-containing nerves. The grafted tissue was examined by use of immunocytochemistry employing a series of primary antisera, lectin histochemistry and transmission electron microscopy. The grafted SCO survived transplantation and contained, in addition to secretory ependymal and hypendymal SCO-cells, also elements immunoreactive with antisera against glial fibrillary acidic protein or S-100 protein. In transplants, SCO-cells produced a material displaying the characteristic immunocytochemical and lectin-binding properties of SCO-cells observed under in-situ conditions. The ependymal cells lined 1–3 small cavities, which contained secretory material. A fully developed structural equivalent of Reissner's fiber was, however, never found. The immunocytochemical and ultrastructural study of the grafted SCO showed an absence of nerve fibers within the graft and suggested a state of enhanced secretory activity. A network of protruding basal lamina structures connected the secretory cells to the newly formed capillaries revascularizing the SCO. One week after transplantation, long-spacing collagen started to appear in expanded areas of such laminar networks and also in the perivascular space. It is suggested (i) that the formation of long-spacing forms of collagen is triggered by factors provided by the SCO-secretory cells, and (ii) that secretory material of the ependymal and hypendymal cells may reach the reticular extensions of the basal lamina. In contrast to the SCO in situ, the grafted SCO-cells showed a positive immunoreaction for neuron-specific enolase. They became surrounded by a S-100-immunoreactive glial sheath that separated them from other transplanted cell types and the adjacent kidney tissue of the host.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 24
    ISSN: 1432-0878
    Schlagwort(e): Gonadotropin-releasing hormone-associated peptide (GAP) ; Luteinizing hormone-releasing hormone (LHRH) ; Brain mapping ; LHRH prohormone ; Immunocytochemistry ; Rat (Wistar-R)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The gonadotropin-releasing hormone-associated peptide (GAP) of the LHRH precursor and the decapeptide LHRH were localized in the rat brain by immunocytochemistry in 12 to 18-day-old animals, by use of thick Vibratome sections and nickel intensification of the diaminobenzidinereaction product. Our results indicate that the GAP portion of the LHRH precursor is present in the same population of neurons that contain LHRH in the rat brain. An important difference observed was that the GAP antiserum, in contrast to LHRH antisera, stained several perikarya in the medial basal hypothalamus. GAP-immunoreactive perikarya were observed in the following regions: the olfactory bulb and tubercle, diagonal band of Broca, medial septum, medial preoptic and suprachiasmatic areas, anterior and lateral hypothalamus, and several regions of the hippocampus. In addition to the preoptico-terminal and the septopreoptico-infundibular pathways, we also observed GAPimmunopositive processes in several major tracts and areas of the brain, including the amygdala, stria terminalis, stria medullaris thalami, fasciculus retroflexus, stria longitudinalis medialis, periventricular plexus, periaqueductal gray of the mesencephalon and extra-cerebral regions, such as the nervus terminalis and its associated ganglion. These results confirm the specificity of previous immunocytochemical results obtained with antisera to LHRH. The presence of GAP immunoreactivity in nerve terminals of the rat brain indicates that GAP or a GAP-like peptide is located in the proper site to serve as a hypophysiotropic substance and/or as a neurotransmitter or neuromodulator.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 25
    ISSN: 1432-0878
    Schlagwort(e): Thyroid gland ; Cathepsin B ; Lysosomes ; Immunocytochemistry ; Diurnal rhythm ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Immunocytochemical localization of cathepsin B and thyroxine (T4) in follicular cells of the rat thyroid gland and plasma concentrations of thyroid stimulating hormone (TSH) were examined at six evenly spaced times over 24 h. By light- and electron microscopy, immunodeposits for cathepsin B were localized in cytoplasmic granules of various sizes, whereas those for T4 were detected mainly in larger granules of the cells and in the colloid lumen. The size and location of cytoplasmic granules showing immunoreactivity for cathepsin B and T4 in the cells varied over 24 h, corresponding to a change in plasma TSH concentrations. These immunopositive large granules appeared in the apical cytoplasm at 12.00 h, when the level of TSH was highest. At 20.00 h when the level of TSH was lowest, T4-positive granules almost disappeared, and cathepsin B-positive small granules were abundantly seen in the basal region. From 00.00 h to 08.00 h, these positive granules changed in the same manner as those seen from 12.00 h to 20.00 h, associated with an increase in plasma TSH levels. These results suggest that newly formed colloid droplets migrate from the apical to the basal regions. Cathepsin B may play a role not only in the degradation of thyroglobulin but in the maturation of thyroid hormones during the migration of the granules.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 26
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 256 (1989), S. 399-410 
    ISSN: 1432-0878
    Schlagwort(e): Dopamine ; Immunocytochemistry ; Brain, invertebrate ; Apis mellifera (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of dopamine-like immunoreactive neurons is described for the brain of the bee, Apis mellifera L., following the application of a pre-embedding technique on Vibratome sections. Immunoreactive somata are grouped into seven clusters, mainly situated in the protocerebrum. Immunoreactive interneurons have been detected in the different neuropilar compartments, except for the optic lobe neuropils. Strong immunoreactivity is found in the upper division of the central body, in parts of the stalk and in the α-lobe layers of the mushroom bodies. A dense network of many immunoreactive fibres surrounds the mushroom bodies and the central body. It forms a number of interhemispheric commissures/chiasmata, projecting partly into the contralateral mushroom body and central body. The lateral protocerebral neuropil contains some large wide-field-neurons. The antennal-lobe glomeruli receive fine projections of multiglomerular dopamine-like immunoreactive interneurons.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 27
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 256 (1989), S. 553-558 
    ISSN: 1432-0878
    Schlagwort(e): Transforming growth factor (TGF)-β ; Myocardium ; mRNA ; Fibroblast ; Cardiomyocyte ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Transforming growth factor-β (TGF-β) is a biologically active polypeptide present in normal tissues as well as transformed cells. Two structurally related forms of this peptide are TGF-β 1 and TGF-β 2. Using freshly isolated cardiomyocytes and non-myocyte heart cells, and a [32P]-labelled cDNA probe to human TGF-β 1, we demonstrated that mRNA for TGF-β 1 could be detected only in the nonmyocyte fraction of heart cells. In the present study, the distribution of TGF-β 1 in the heart was determined by immunofluorescence staining by use of a polyclonal antibody to porcine TGF-β 1 in cryostat sections of rat heart. Immunofluorescence staining was intense around the blood vessels and radially diffuse in the surrounding myocardium.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 28
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 257 (1989), S. 69-75 
    ISSN: 1432-0878
    Schlagwort(e): Inner ear ; Cytoskeletal proteins ; Immunocytochemistry ; Cell motility ; Actin ; Guinea pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Isolated outer hair cells of the guinea pig lacking a cuticular plate and its associated infracuticular network retain the ability to shorten longitudinally and become thinner. Membrane ghosts lacking cytoplasm retain the cylindrical shape of the hair-cell, and although they do not shorten, they retain the ability to constrict and become thinner. These data suggest that cytoplasmic components are associated with outer hair-cell longitudinal shortening and that the lateral wall is responsible for maintaing cell shape and for constriction. Actin, a protein associated with the cytoskeleton and cell motility, is thought to be involved in outer hair-cell motility. To study its role, actin was localized in isolated outer hair cells by use of phalloidin labeled with fluorescein and antibodies against actin coupled to colloidal gold. In permeabilized guinea-pig hair cells stained with phalloidin, actin filaments are found along the lateral wall. In frozen-fixed hair cells actin filaments are distributed uniformly throughout the cytoplasm. Electron-microscopic studies show that antibodies label actin throughout the outer hair-cell body. Thus cytoplasmic actin filaments may provide the structural basis for the contraction-like events.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 29
    ISSN: 1432-0878
    Schlagwort(e): Antigen localization ; FMRFamide-like immunoreactivity ; Immunocytochemistry ; Invertebrate ganglia ; Small cardioactive peptide-like immunoreactivity ; Hirudo medicinalis (Annelida)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distributions of small cardioactive peptide (SCP)- and FMRFamide-like immunoreactivities in the central nervous system of the medicinal leech Hirudo medicinalis were studied. A subset of neurons in the segmental ganglia and brains was immunoreactive to an antibody directed against SCPB. Immunoreactive cell bodies were regionally distributed throughout the nerve cord, and occurred both as bilaterally paired and unpaired neurons. The majority of the unpaired cells displayed a tendency to alternate from side to side in adjacent ganglia. A small number of neurons were immunoreactive only in a minority of nerve cords investigated. Intracellular injections of Lucifer yellow dye and subsequent processing for immunocytochemistry revealed SCP-like immunoreactivity in heart modulatory neurons but not in heart motor neurons. FMRFamide-like immunoreactivity was also detected in cell bodies throughout the central nervous system. A subset of neurons contained both SCP- and FMRFamide-like immunoreactivities; others stained for only one or the other antigen. These data suggest that an antigen distinct from FMRFamide is responsible for at least part of the SCP-like immunoreactivity. This antigen likely bears some homology to the carboxyl terminal of SCPA and SCPB.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 30
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 256 (1989), S. 303-307 
    ISSN: 1432-0878
    Schlagwort(e): Arachnoid cells ; Tight and gap junctions ; Cold injury ; Ultrastructure ; Freeze-fracture technique ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The junctional complexes of cells in the outer arachnoid layer overlying the cerebral cortex of 2-week-old rats were examined with freeze-fracture electron microscopy up to 60 min after transcranial cold injury to the dorsal surface of the brain. Within 30 min after injury, areas of gap and tight junctions with morphological features characteristic of junction formation and/or junction disruption were found scattered among normal junctional complexes in some arachnoid cells. Within 60 min after injury, tight junctions with features typical of less leaky zonulae occludentes were present in all arachnoid cells examined. These morphological features include increases in the number of tight junctional strands and the number of strand-to-strand anatomoses. Gap junctions were interspersed among the tight junctional strands, and many were completely encircled by the strands. The increase in the number and complexity of the tight junctional strands in response to brain injury may be the morphological basis for the maintenance of the cerebrospinal fluid-blood dural barrier.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 31
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 256 (1989), S. 559-565 
    ISSN: 1432-0878
    Schlagwort(e): Retrograde tracing ; Immunocytochemistry ; Vascular innervation ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The origin of nerve fibers to the superficial temporal artery of the rat was studied by retrograde tracing with the fluorescent dye True Blue (TB). Application of TB to the rat superficial temporal artery labeled perikarya in the superior cervical ganglion, the otic ganglion, the sphenopalatine ganglion, the jugular-nodose ganglionic complex, and the trigeminal ganglion. The labeled perikarya were located in ipsilateral ganglia; a few neuronal somata were, in addition, seen in contralateral ganglia. Judging from the number of labeled nerve cell bodies the majority of fibers contributing to the perivascular innervation originate from the superior cervical, sphenopalatine and trigeminal ganglia. A moderate labeling was seen in the otic ganglion, whereas only few perikarya were labeled in the jugular-nodose ganglionic complex. Furthermore, TB-labeled perikarya were examined for the presence of neuropeptides. In the superior cervical ganglion, all TB-labeled nerve cell bodies contained neuropeptide Y. In the sphenopalatine and otic ganglia, the majority of the labeled perikarya were endowed with vasoactive intestinal polypeptide. In the trigeminal ganglion, the majority of the TB-labeled nerve cell bodies displayed calcitonin gene-related peptide, while a small population of the TB-labeled neuronal elements contained, in addition, substance P. In conclusion, these findings indicate that the majority of peptide-containing nerve fibers to the superficial temporal artery originate in ipsilateral cranial ganglia; a few fibers, however, may originate in contralateral ganglia.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 32
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 256 (1989), S. 447-456 
    ISSN: 1432-0878
    Schlagwort(e): MAP2 ; Actin ; Dendritic spines ; Spine apparatus ; Spine synapses ; Postsynaptic density ; Synaptic plasticity ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of MAP2 and actin in dendritic spines of the visual and cerebellar cortices, dentate fascia, and hippocampus was determined by using immunogold electron microscopy. By this approach, we have confirmed the presence of MAP2 in dendritic spines and identified substructures within the spine compartment showing MAP2 immunoreactivity. MAP2 immunolabeling was mainly associated with filaments which reacted with a monoclonal anti-actin antibody. Also, by immunogold double-labeling we colocalized MAP2 with actin on the endomembranes of the spine apparatus, smooth endoplasmic reticulum, and in the postsynaptic density. Labeling was nearly absent in axons and axonal terminals. These results indicate that MAP2 is an actin-associated protein in dendritic spines. Thus, MAP2 may organize actin filaments in the spine and endow the actin network of the spine with dynamic properties that are necessary for synaptic plasticity.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 33
    ISSN: 1432-0878
    Schlagwort(e): Insulin-related peptide ; Immunocytochemistry ; Immunochemical characterization ; Pancreas ; Ambystoma mexicanum (Urodela)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The pancreas of the axolotl, Ambystoma mexicanum, was investigated by immunocytochemical methods for the presence of immunoreactivity to a number of antisera raised against mammalian insulins. All anti-insulin antisera tested revealed substantial amounts of reaction products confined solely to the aldehyde-fuchsinophilic B cells of the endocrine pancreas. The reactive cell population was detected by use of one polyclonal antiserum against bovine insulin and eight different monoclonal antibodies against insulins from various mammalian species. Six of these antibody clones have known specificity to sub-regions of the insulin molecule. Additionally, fractions of an ethanol-HCl extract of pancreatic tissue from Ambystoma was studied in both conventional dot-blot tests by means of the same panel of antibodies and a two-site sandwich time-resolved immunofluorometric assay for human insulin involving two of the monoclonal antibodies. These experiments support the immunocytochemical observations by demonstrating the existence of an insulin-related peptide with a great deal of structural resemblance to mammalian insulins and displaying antigenic determinants in common at least with the amino acid residues A8–10 and B26–30. In conclusion, we interpret the findings as indicating that the immunocytochemically revealed tissue bound antigen in the Ambystoma pancreatic B-cells may be a peptide related to human insulin.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 34
    ISSN: 1432-0878
    Schlagwort(e): Immunocytochemistry ; Prolactin cells ; Gonadotropic cells ; ACTH cells ; Folliculo-stellate cells ; Rana pipiens (Anura)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The colloidal gold immunocytochemical technique was used to determine the ultrastructural features of the glandular cells in the pituitaries of male frogs, Rana pipiens, both in vivo and after superfusion in vitro. Specific reactions to antisera against bullfrog gonadotropins, human prolactin, and synthetic 1–39 corticotropin allowed identification of the 3 corresponding types of glandular cells. No immunoreaction was obtained with antisera against human or ovine-growth hormone, human β-thyrotropin hormone, and bovine S-100 protein. General morphological features of these immunocytochemically identified glandular cells were similar to those of equivalent cells previously described in other amphibian species. Non-glandular folliculo-stellate cells were distinctive. In freshly removed pituitaries, these folliculo-stellate cells contained lysosome-like structures, but did not show phagocytic vacuoles in the cytoplasm; they contained many mitochondria, and the Golgi complex and endoplasmic reticulum were relatively undeveloped. After 4 or 18 h of superfusion, some immunoreactive gonadotropic, prolactin, and corticotropic cells showed degeneration and destruction. In the same gland, folliculo-stellate cells retained a viable appearance, but showed phagocytic vacuoles containing secretory granule-like structures which were immunoreactive to gonadotropic, prolactin, and corticotropic antibodies. Some folliculo-stellate cells showed phagocytic vacuoles containing complete glandular cells. These results suggest that superfusion causes a destruction of some of the glandular cells, and that folliculo-stellate cells act as phagocytes when cellular debris or moribund cells are present in the intercellular space in the pituitary parenchyma.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 35
    ISSN: 1432-0878
    Schlagwort(e): S-100 protein ; Immunocytochemistry ; Saccus vasculosus ; Pituitary gland, pars nervosa ; Mustelus manazo, Scyliorhinus torazame(Elasmobranchii)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary S-100 protein-immunoreactive cells were demonstrated by immunocytochemical procedures in the hypophysis and saccus vasculosus of two species of elasmobranchs (Mustelus manazo and Scyliorhinus torazame). In the saccus vasculosus of M. manazo, immunoreactivity was detectable exclusively in the fibrous portions interposed between the epithelial layer and the blood vessels. In the neurohypophysis, tanycytes and astrocytes of the median eminence were immunostained, but only a few labeled cells were found in the neurointermediate lobe. In S. torazame, the neurohypophysis displayed a similar distribution of immunoreactivity, but there were no labeled cells in the saccus vasculosus. In both species, none of the glandular cells of the hypophysis displayed immunoreactivity. Electron-microscopic examination showed that the immunostained cells in the saccus vasculosus correspond to astrocytes.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 36
    ISSN: 1432-0878
    Schlagwort(e): Development ; Intrapulmonary chemoreceptor ; Immunocytochemistry ; Morphometry ; Rabbit
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution, frequency and size of neuroepithelial bodies (NEB) were studied in lungs of rabbits during different stages of development (27-day fetus, newborn, 6, 11, 21, 28 and 56 days postnatally). NEB were visualized by immunostaining with monoclonal antibody against serotonin. Detailed quantitiation of NEB was performed by use of camera lucida drawings of immunostained serial sections from the same anatomical region, i.e. the lower lobe of the left lung. The total number of NEB was counted and expressed per epithelial length of airway, surface area and volume. The size of NEB defined as surface area as well as the position of NEB in relation to the airway bifurcations was assessed in airways of different sizes. The overall number and size of NEB were found to increase during the immediate perinatal period followed by a sharp decline at 56 days of age. The number of NEB peaked at 6 days postnatally (mean 175.5 NEB/mm3 of airway epithelium) and declined significantly (3.0 NEB/mm3) at 56 days of postnatal age. The size of NEB reached its maximum at 11 days (mean surface area 659.54 μm2, with the largest NEB measuring 1839.98 μm2). By 56 days of age, NEB became significantly smaller (mean surface area 177.29 μm2) consisting of small clusters of cells situated deep within the airway epithelium. At all ages, about half of all NEB (mean 47.6%) were localized within the small peripheral airways with up to 63.9% located at airway bifurcations. These findings indicate that the “functional activity” of NEB may be confined predominantly to the perinatal period. The postulated functions of NEB include those of intrapulmonary hypoxia-sensitive chemoreceptors and/or endocrine-paracrine activity in the lung. Such function(s) may be important during adaptation to extrauterine life as well as for growth and development of the lung.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 37
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 256 (1989), S. 45-51 
    ISSN: 1432-0878
    Schlagwort(e): Testis ; Leydig cells ; Basement membrane ; Laminin ; Collagen ; Immunocytochemistry ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Rat testes were examined by conventional and immunolabeling transmission electron microscopy. Ultrastructurally identifiable continuous basement membranes were found around seminiferous tubules and the interstitial capillaries. Patches of basement membrane were, additionally, found on free surfaces of Leydig cells, between two Leydig cells, and in macrophage-Leydig cell contact sites. The ultrastructural findings were confirmed by immunocytochemical localization of laminin and collagen type IV in the same areas. A close association between the capillary basement membranes and the surfaces of perivascular Leydig cells was also observed. The possible basement membrane-mediated interactions of Leydig cells with other testicular structures, together with the novel bioactive products and regulators of Leydig cells, support the role of these cells as exceptionally complex regulatory centers of testicular functions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 38
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 256 (1989), S. 153-158 
    ISSN: 1432-0878
    Schlagwort(e): Acetylcholine ; Acetylcholinesterase ; Cholin-acetyltransferase ; Immunocytochemistry ; Visual system ; Calliphora erythrocephala (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of putative cholinergic neurons in the lamina of the blowfly Calliphora erythrocephala was studied by immunocytochemical and histochemical methods. Three different antibodies directed against the AChsynthesizing enzyme, choline acetyltransferase (ChAT), revealed a cholinergic population of fibres running parallel to the laminar cartridges, which have branch-like structures at the distal lamina border. Cell bodies in the chiasma next to the lamina border were also labelled by the anti-ChAT antibodies. Monopolar cell bodies in the nuclear layer were faintly labelled. The distribution of the acetylcholine hydrolyzing enzyme, acetylcholine esterase (AChE), was revealed by histochemical staining and was similar to the ChAT immunocytochemistry. The arrangement of ChAT positive fibres in transverse and longitudinal sections and the distribution of AChE stained fibres indicate that the amacrine cells of the lamina are cholinergic cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 39
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 256 (1989), S. 159-166 
    ISSN: 1432-0878
    Schlagwort(e): Pancreas, endocrine ; Cysteamine ; Somatostatin ; Insulin secretion ; Glucose ; Immunocytochemistry ; Mouse (NMRI)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary To evaluate the previously reported depletion of pancreatic somatostatin by cysteamine (β-mercaptoethylamine), mice were injected subcutaneously with the drug at 300 mg/kg. Immunocytochemical analysis performed on sections from tissue taken at 4 h after the injection revealed an elimination of somatostatin-14-like immunoreactivity without alterations in the somatostatin-28(1 – 12)-like immunoreactivity. In sections from tissues taken at 24 h after injection, no differences between cysteamine-injected animals and controls were observed. Immunochemical analysis of somatostatin-14-like immunoreactivity in pancreatic extracts showed a significant reduction of the concentration (P〈 0.001). In contrast, no change in the insulin concentration was observed. Functionally, cysteamine lowered the plasma glucose levels at l h after injection; this effect persisted for 6 h. Plasma insulin levels were likewise reduced transiently by cysteamine. Concomitant administration of somatostatin did not influence these effects of cysteamine. The plasma glucose-lowering effect of cysteamine was seen also in alloxan-diabetic mice. We conclude that cysteamine alters the immunoreactive characteristics of pancreatic somatostatin without affecting the immunoreactivity of insulin, and that cysteamine transiently reduces plasma glucose and insulin levels
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 40
    ISSN: 1432-0878
    Schlagwort(e): FMRFamide ; Cholecystokinin ; Immunocytochemistry ; Insect visual system ; Neural development ; Calliphora erythrocephala (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The adult optic lobes of the blowfly Calliphora erythrocephala were found to be innervated by more than 2000 neurons immunoreactive to antisera raised against the neuropeptides FMRFamide, its fragment RFamide, and gastrin/cholecystokinin (CCK). All of the CCK-like immunoreactive (CCK-IR) neurons also reacted with antisera to RFamide, FMRFamide and pancreatic polypeptide. A few RFamide/FMRFamide-like immunoreactive (RF-IR) neurons did not react with CCK antisera; they reacted instead with antisera to Leu-enkephalin and Met-enkephalin-Arg6-Phe7. The RF-IR neurons are, thus, heterogeneous with respect to their contents of immunoreactive peptides. Two of the RF-IR neuron types innervating the adult optic lobes could be traced in their entirety only after following their postembryonic development, because of the complexity of the trajectories of the immunoreactive neuronal process in the adult insect. The majority of the cell bodies of the RF-IR and CCK-IR neurons lie within the optic lobes and are derived from imaginal neuroblasts of the inner and outer optic anlagen. Six of the peptidergic neurons are, however, metamorphosing larval neurons with their cell bodies in the central part of the protocerebrum. The full extent of immunoreactivitiy is not attained in some of the neurons until the late pupal or early adult stage. The larval optic center was also found to be innervated by neurons immuno-reactive with both RFamide and CCK antisera. The cell bodies of these RF-IR/CCK-IR neurons are located near the developing lamina (one on each side). In the 24 h pupa, the cell bodies of these neurons are still immunoreactive, but thereafter they cannot be immunolabeled apparently due to cell death or a change in transmitter phenotype.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 41
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 255 (1989), S. 645-650 
    ISSN: 1432-0878
    Schlagwort(e): Pituitary, pars distalis ; Differentiation ; Organ culture ; Immunocytochemistry ; Rat (Sprague-Dawley, CFY)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary An immunohistochemical study was performed to determine the capacity of early fetal pituitaries to differentiate into specific hormone-synthesizing tissue in the absence of any influence from the central nervous system. Rathke's pouches from rats were removed from their juxtadiencephalic position on day 11 and 12 of gestation and maintained for 2–7 days in a chemically defined culture medium (M 199) without antibiotics and serum supplementation. The immunocytochemical observations provided evidence for the differentiation of ACTH-, TSH-gb-, LH-gb-, FSH-gb-, GH- and PRL-synthesizing cells in the isolated organ cultured from 11 to 12-day-old pituitary primordia. The appearance of specific hormone-synthesizing cells in vitro displayed a delay of 1.5–2 days compared to the day of appearance in vivo, however, the sequential order of developmental events occurred as observed in vivo. The present results suggest that endocrine or neuroendocrine signals are not required for the expression of specific secretory functions of fetal pituitaries, at least at an age of 11–12 days.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 42
    ISSN: 1432-0878
    Schlagwort(e): Hypophyseal pars tuberalis ; (TSH), Thyrotropin ; Immunocytochemistry ; Photoperiod ; Phodopus sungorus
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Specific secretory cells in the hypophyseal pars tuberalis of Djungarian hamsters maintained under different photoperiods were investigated immunocytochemically by means of the colloidal gold technique using antibodies against rat thyrotropin (TSH). Secretory cells of animals kept under long photoperiods (LD16:8) showed positive staining of secretory granules (diameters 90–130 nm), whereas other intracellular structures were free of immunoreactivity. In animals kept under short photoperiods (LD8:16) secretory cells displayed increased numbers of secretory granules, but these organelles were devoid of immunoreactivity. In contrast, immunoreactivity of thyrotropes in the pars distalis did not differ between the two groups of animals investigated. The present results confirm earlier light-microscopical studies that in the pars tuberalis specific secretory cells show TSH-like immunoreactivity; however, they differ in their reactivity pattern from classical thyrotropes in the pars distalis.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 43
    ISSN: 1432-0878
    Schlagwort(e): Neuropeptides ; Monoclonal antibodies ; Immunocytochemistry ; Endocrine system ; Nervous system ; Leptinotarsa decemlineata (Say)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Monoclonal antibodies were developed against peptidergic neurons in the nervous and endocrine tissues of the Colorado potato beetle by the immunization of mice with unpurified homogenates of these tissues. Methods were optimized to enhance chances for successful antibody production and selection, such as the pretreatment of the beetles, preparation of the immunogen, and screening hybridomas. Although only sub-microgram quantities of peptide antigen were used, many hybridomas generated antibodies recognizing peptidergic neurons in immunocytochemical procedures. A panel of 13 monoclonal antibodies anti-Colorado potato beetle (MACs) were harvested. All MACs stained different populations of peptidergic neurons, some of which had not been revealed by previously applied identification methods. Apart from the intrinsic glandular cells in the corpora cardiaca, immunoreactive neurosecretory neurons were revealed in medial and lateral groups in the protocerebrum and in the suboesophageal ganglion. These have axons terminating in the corpora cardiaca, and the neurosecretory granules can be revealed with the immunogold method. It is suggested that the immunoreactive substances represent neuropeptides or precursors of different kinds. Interneurons in other locations in the central and visceral nervous system have immunoreactive axonal projections that do not leave the ganglia. The set of MACs obtained is useful for neuroanatomical studies, for characterizing the secretory products, and for a further delineation of peptidergic communication channels in the insect body.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 44
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 255 (1989), S. 215-224 
    ISSN: 1432-0878
    Schlagwort(e): Transglutaminase ; Immunocytochemistry ; Induction ; Tissue compartments ; Tissue integrity ; Human
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Tissue transglutaminase is an intracellular enzyme without established physiological function. Biochemically it can be detected in all organs, but no systematic in situ localization has been carried out so far. Here we report the immunohistochemical localization of transglutaminase in human tissues using an affinity purified, monospecific anti-human transglutaminase antibody. It is shown that the widespread organ distribution of the enzyme is the consequence of its occurrence in ubiquitous cell types such as endothelium and smooth muscle cells. Some organ-specific cell types express the enzyme constitutively (mesangial cells, renomedullary interstitial cells, thymic subcapsular epithelium, colonic pericryptal fibroblasts), while in others it seems to be induced either by external stimuli (epithelium of the female breast) or as part of their differentiation/maturation program (developing nephrons, enterocytes of the small intestine). The presence of tissue transglutaminase can be demonstrated in derivatives of all germ layers and in the trophoblast. The functional implications of these findings are presently unknown; however, based on its distribution the role of this enzyme in compartmentation and preservation of tissue integrity against stress may be suggested.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 45
    ISSN: 1432-0878
    Schlagwort(e): Pituitary gland ; Neural lobe ; Intermediate lobe ; Intraventricular graft ; Immunocytochemistry ; Electron microscopy ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Neurointermediate lobes from adult or 10-dayold rats were implanted by a stereotaxic procedure into the third ventricle of adult male rats, in an area close to the paraventricular nucleus. They were examined, using immunocytochemical and ultrastructural techniques, at times ranging from 1 week to 8 months. All grafts were recovered in a healthy condition although some rejection of the tissue was detected at the 1and 2-week stages. In the neural lobe, clusters of pituicytes were scattered among the loose network of capillaries, most of which had a fenestrated endothelium. The intermediate lobe remained organized in compact avascular lobules. Axons similar to those projecting into the neurointermediate lobe in situ, but also axons of other types (e.g., somatostatinergic, enkephalinergic) penetrated the grafts. Synapses with melanotrophic cells in the intermediate lobe and neurohaemal contacts in the neural lobe were frequent from 2 1/2 months after transplantation. Immunocytochemical and ultrastructural characteristics indicated intense secretory stimulation of the melanotrophic cells in the early stages. All cells enclosed in a same glandular lobule reacted in a similar manner. In later stages, when re-innervation occurred, the cells recovered their initial characteristics. The overall effect of the re-innervation of the intermediate lobe grafted in this location is inhibitory, as in the lobe in situ.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 46
    ISSN: 1432-0878
    Schlagwort(e): Spinal cord ; Dorsal root ganglia ; Skin ; Immunocytochemistry ; Neuropeptides ; Mutilated foot rat (Sprague-Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The mutilated foot rat is a mutant with autosomal recessive sensory neuropathy and frequent mutilation of the hindlimbs. Decreased numbers of dorsal root ganglion cells and diminished sensitivity to painful stimuli are characteristics of these animals. By use of immunocytochemistry, changes in the distributions of peptides involved in sensory and/or autonomic regulation, i.e. calcitonin generelated peptide (CGRP), tachykinins, enkephalin and neuropeptide Y in spinal cord, dorsal root ganglia and skin of these animals, were studied. In comparison with normal litter-mate controls, the dorsal horn of mutilated foot rats contained substantially fewer CGRP and tachykinin-immunoreactive fibres but more fibres immunoreactive for enkephalin. Many enkephalin-immunoreactive cell bodies were also found in the dorsal horn of the mutants, by contrast none were visible in control animals. Neuropeptide Y immunoreactivity was, however, unchanged in the spinal cord of the mutants. In the dorsal root ganglia of the mutants, the number of CGRPor tachykinin-immunoreactive cells and their proportion to total neuronal numbers were significantly less in comparison with normal controls. The diameter range of CGRP- and tachykinin-immunoreactive cells shifted from small (15–25 μm) to medium size (25–45 μm) as revealed by frequency distribution histograms. The skin from the affected foreand hindlimbs of the mutant rats, in keeping with fewer CGRP- and tachykinin-immunoreactive cells in the dorsal root ganglia, contained substantially less fibres immunoreactive for CGRP and tachykinins; a difference that was not seen in skin of unaffected areas (whiskers and snout). By contrast, neuropeptide Y-immunoreactive fibres showed a normal distribution around blood vessels and sweat glands of mutilated foot rats. The data suggest that diminished pain perception in the mutilated foot rat is related to loss of peptide-containing sensory neurones. Furthermore, the intraspinal increase of enkephalinergic neurones in the dorsal horn, concomitant with the decreased number of primary sensory neurones, may also play a contributory rôle in reducing pain thresholds.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 47
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 256 (1989), S. 167-173 
    ISSN: 1432-0878
    Schlagwort(e): Cell proliferation ; Immunocytochemistry ; Lung ; Bronchioles ; Alveoli, lung ; Proliferating cell nuclear antigen ; Type II pneumocyte ; Clara cell ; Mouse (various strains)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Proliferating cell nuclear antigen is expressed in cells from late G1 through the S-phase of the cell cycle. Therefore, antibodies directed against this molecule should provide a probe for labeling immunocytochemically the nuclei of proliferating cells. Herein we demonstrate the feasibility and reliability of this technique by quantifying immunostained pulmonary nuclei. We applied polyclonal and monoclonal antisera to alveolar and bronchiolar pulmonary epithelial cells in various proliferative states in tissue-sections and in vitro. A/J mice had a slightly higher labeling index than C57BL/6J mice, and proliferation in both strains increased dramatically after butylated hydroxytoluene treatment produced compensatory hyperplasia of Type-II pneumocytes. Immunostaining in fetal and neonatal lung samples from mice was higher than in adults. Spontaneous lung adenomas had a higher labeling index than the surrounding normal lung tissue. In addition, new data contained herein demonstrate a strain difference in proliferation of bronchiolar epithelial cells, and quantify the extent to which BHT-induced lung damage increases these proliferative rates. This mammalian nuclear antigen did not cross-react with antiserum to a functionally related bacterial protein, the beta subunit of E. coli DNA polymerase-III holoenzyme.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 48
    ISSN: 1432-0878
    Schlagwort(e): Pars distalis ; Prolactin/thyrotropic cells ; TRH ; Immunocytochemistry ; Morphometry ; Rana perezi (Anura)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The effects of synthetic thyrotropin-releasing hormone on pituitary prolactin and thyrotropic cells were investigated in adult male Rana perezi (formerly Rana ridibunda) frogs. Animals were given daily injections of synthetic thyrotropin-releasing hormone into the dorsal lymph sac. Prolactin and thyrotropic cells were identified by the colloidal-gold method, using anti-human prolactin and anti-human-β-thyrotropin hormone as primary antisera. The stereological parameters of the rough endoplasmic reticulum, Golgi complex, and secretory granules of prolactin and thyrotropic cells were evaluated by ultrastructural morphometry (point-counting method). Thyrotropin-releasing hormone caused cytological changes in both cell-types which were consistent with increased synthesis and release of both prolactin and thryrotropin. These changes were still significant after 48 h treatment in the case of thyrotropic cells, while in prolactin cells the thyrotropin-releasing hormone increased the number of secretory granules. After 6 days, the cells resembled essentially those used as controls. These results indicate that thyrotropin-releasing hormone stimulates the synthesis and release of prolactin and thyrotropin, and that the response of each cell type to this hypothalamic stimulus follows a different time-course.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 49
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 255 (1989), S. 523-527 
    ISSN: 1432-0878
    Schlagwort(e): Peptides ; Small intensely fluorescent (SIF) cell ; Neuropeptide coexistence ; Inferior mesenteric ganglion ; Immunocytochemistry ; Guinea pig
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Coexistence of peptides in the small intensely fluorescent cells was demonstrated by immunocytochemistry for met-enkephalin-Arg-Gly-Leu, vasoactive intestinal polypeptide, somatostatin, neuropeptide Y and dynorphin. In the extreme example, a single cell was immunoreactive to all 5 peptides examined. Four peptides coexisted in 8% and three peptides in 13% of SIF cells. In 10% of SIF cells no peptide immunoreactivity could be detected. The most prevalent peptide was met-enkephalin (in 46% of cells), then vasoactive intestinal polypeptide (45%), somatostatin (39%), neuropeptide Y (31%) and dynorphin (24%). Met-enkephalin and vasoactive intestinal polypeptide coexisted most commonly (25%).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 50
    ISSN: 1432-0878
    Schlagwort(e): Endocrine heart ; Estradiol ; Autoradiography ; Immunocytochemistry ; Co-localization ; CDD/ANP gene regulation ; Rat (Sprague-Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Atrial myoendocrine cells of rat were investigated regarding estradiol uptake. It was found that, in addition to their specific endocrine function of producing cardiac polypeptides of the cardiodilatin/atrial natriuretic peptide (CDD/ANP) family, these cells also specifically accumulate radiolabeled estradiol. This co-localization supports the view that steroid hormones play an important role in the regulation of the CDD/ANP gene.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 51
    ISSN: 1432-0878
    Schlagwort(e): Prolactin cells ; Growth hormone cells ; In situ hybridization ; Immunocytochemistry ; Cytogenesis ; Rat (Wistar-Imamichi)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Cytogenesis of growth hormone and prolactin cells in the rat pituitary gland was studied using in situ cDNA-mRNA hybridization and immunocytochemistry. Frozen or Paraplast sections of fetal and neonatal pituitaries were hybridized with 3H-cDNAs for rat prolactin or growth hormone, and were then processed for autoradiography. A number of growth hormone mRNA-positive cells were encountered throughout the anterior lobe on day 19 of gestation. Individual variaction in growth hormone gene expression was observed between fetuses at day 19 of gestation (6 out of 8 fetuses examined were positive for growth hormone mRNA). In contrast, growth hormone mRNA was detected in the all fetuses examined on day 20 or later. The autoradiographic signal (number of reduced silver grains) appeared to increase with later stages of development. Fetal growth hormone mRNA-positive cells were evenly scattered throughout the anterior lobe. Most of them were isolated, however, small clusters of several growth hormone cells were infrequently observed. Prolactin mRNApositive cells were found first on the 22nd day (the last day of gestation) in 3 of 6 fetuses examined, but were rarely observed on earlier gestational days. By postnatal day 8, prolactin mRNA-positive cells were numerous and the grain density over prolactin cells increased. Both growth hormone and prolactin cells were found as early as 18 days of gestation using immunocytochemistry, although the number of positive cells was very small at this stage. Immunoreactive growth hormone cells increased sharply in number during the next 24 h, while the number of prolactin cells remained scarce until birth. The results suggest that many growth hormone cells are still in an immature state at 20∶00 of day 18 and that many begin to synthesize growth hormone mRNA during next 14 h. On the other hand, no substantial prolactin gene expression appears to take place until after birth.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 52
    ISSN: 1432-0878
    Schlagwort(e): Adrenal medullary endothelial cells ; Pheochromocytoma (PC12) cells ; Co-culture ; Cell surface extracts ; Adhesion ; Cell-cell interactions ; Bovine ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Chromaffin cells in the adrenal medulla are found in close proximity to capillary endothelial cells, thereby forming the classical endocrine complex. To examine the possible chemical basis of their interaction in more detail, we have grown bovine adrenal medullary endothelial (BAME) cells in monolayer cultures and added to them pheochromocytoma (PC12) cells, a chromaffin tumor cell line of rats. The PC12 cells were chosen because of the similarities they share with adrenal medullary chromaffin cells. PC12 cells rapidly attached to BAME cells cultures, their rate of adhesion being significantly enhanced over binding of PC12 cells to either uncoated plates or to monolayers of unrelated cell cultures. Consistent with this observation, we noted that the extracellular matrix (ECM) derived from the BAME cells did not enhance PC12 cell adhesion and did not promote neurite sprouting as previously described for ECM derived from corneal endothelial cells. The specific adhesion between PC12 and BAME cells could be abolished by cell surface extracts derived from these two cells but not by extracts derived from unrelated cell types. This activity was heat-labile, sensitive to trypsin and, to a lesser extent, to neuraminidase. We therefore conclude that PC12 cells may interact with BAME cells by specific proteinaceous adhesive factors associated with their plasma membranes. These interactions might represent the formative role of cell-cell contacts in the organization of the developing adrenal gland.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 53
    ISSN: 1432-0878
    Schlagwort(e): SEM ; TEM ; Interstitial cell ; Myenteric plexus ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary An extensive cellular network becomes visible over the myenteric plexus of the rat after removal of the overlying tissues under the scanning electron microscope. The cells are mainly stellate and have many slender processes via which they interconnect. They form a three-dimensional network and are closely associated with the ganglia and nerve bundles, and also extend over the smooth muscle cells. They are considered to correspond to the interstitial cells of Cajal because of their peculiar arrangement and their topography. Transmission electron-microscopic evidence demonstrates that the majority of those cells have features of fibroblasts. Gap junctions and intermediate junctions are observed between these fibroblast-like cells, and also between them and smooth muscle cells. Examination of serial thin sections reveals that single fibroblast-like interstitial cells connect to both circular and longitudinal muscle cells via gap junctions. It is suggested that the network of interstitial cells conducts electrical signals.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 54
    ISSN: 1432-0878
    Schlagwort(e): Nucleus intercollicularis ; α2-Adrenergic receptors ; Estrogen receptors ; Quantitative autoradiography ; Immunocytochemistry ; Japanese quail, Coturnix coturnix japonica (Aves, Phasianiformes)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The nucleus intercollicularis is an important site in the control of vocalization in birds. In oscines, a subregion of the nucleus intercollicularis called the dorso-medial intercollicular nucleus appears to play a key role in this process because it receives the majority of the projections from the nucleus robustus archistriatalis and sends most of the projections to the motor nucleus of the hypoglossal nerve. In this paper, we present neurochemical studies of the nucleus intercollicularis in the Japanese quail which suggest the presence of heterogeneity within this structure. One rostral band contains high densities of cholinergic muscarinic receptors identified by quantitative autoradiography using tritiated N-methylscopolamine as the ligand. A caudal dorso-medial region is specifically labeled by estrogen receptors identified using immunocytochemistry and by α2-adrenergic receptors which were quantified by autoradiography using tritiated para-amino-clonidine. This latter sub-region is possibly equivalent to the dorso-medial intercollicular nucleus of oscines. Additional track-tracing studies should be performed to confirm this homology. The coexistence of estrogen and α2-adrenergic receptors within the same structure suggests important functional connections between steroid action and catecholaminergic systems in the brain.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 55
    ISSN: 1432-0878
    Schlagwort(e): Gastrin ; Gastrin-releasing peptide ; Bombesin ; Stomach ; Autonomic innervation ; Immunohistochemistry ; Guinea pig ; Rat ; Dog ; Man
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The relationship between bombesin-like immunoreactive (bombesin-LI) nerve fibres and gastrin-LI G-cells was examined in gastric antral mucosa from guineapig, rat, dog and man using a double-labelling fluorescence immunohistochemical technique. The greatest density of bombesin-LI nerve fibres was found within the basal mucosa in all species and the density of innervation decreased towards the luminal surface. Most G-cells were in a band occupying approximately the middle third of the mucosa. The proportion of G-cells found within a distance of 2 μm from bombesin-LI nerve fibres was low in all species (6% in the guinea-pig, 22% in the rat, 14% in the dog, and 9% in the human). It is proposed that the neuropeptide released from bombesin-LI antral mucosal nerve fibres traverses distances of greater than several μm to reach the target G-cells. This may be achieved by passage through the mucosal microcirculation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 56
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 257 (1989), S. 263-268 
    ISSN: 1432-0878
    Schlagwort(e): Retinol ; Vacuoles ; Immunohistochemistry ; Plasma proteins ; Hepatocytes ; Rat
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The vacuoles occurring in rat hepatocytes after intraportal injection of retinol (33 or 67 μg) were examined immunohistochemically using respective antibodies against rat albumin, human retinol-binding protein, human ceruloplasmin, human α 1-antitrypsin, human transferrin, and human prealbumin as representative plasma proteins. The occurrence of the vacuoles reached a numerical maximum 30 min after injection of 67 μg retinol, followed by a temporal decrease. Hepatocytes from control rats, which had been intraportally injected with either blood plasma diluted to 2/3 concentration or with retinol palmitate solvent (castor oil) dissolved in blood plasma, showed immunoreactive fine granules without the occurrence of vacuoles in the cytoplasm. Identical vacuoles in serial sections appeared immunohistochemically either immunoreactive or non-immunoreactive for all the antibodies used, with rare exceptions. The occurrence of several rare exceptions suggested that 2 kinds of vacuoles might be formed in different cytoplasmic compartments. A zonal distribution of vacuoles was apparent in the hepatic laminae (or acini) within the liver lobules. The vacuoles were predominantly distributed in zone 2, and to a lesser extent in zone 3 and zone 1 in that order.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 57
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 255 (1989), S. 657-662 
    ISSN: 1432-0878
    Schlagwort(e): Thyrotropin-releasing hormone (TRH) ; Development, ontogenetic ; Anterior hypothalamus ; Immunocytochemistry ; Domestic mallard
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Developmental changes of thyrotropin-releasing hormone (TRH)-immunoreactive structures in the brain of mallard embryos were studied by means of immunocytochemistry (PAP technique). The primary antibody was generated against synthetic TRH. Immunoreactive neurons were first detected in the hypothalamus of 14-day-old embryos. By day 20, increasing numbers of immunoreactive perikarya were observed in the paraventricular nucleus, anterior preoptic region and supraoptic region. Immunoreactive fiber projections were seen in the median eminence as early as embryonic day 20; they occurred also in some extrahypothalamic regions (lateral septum, accumbens nucleus). The number and staining intensity of the cell bodies increased up to hatching, and continued to increase during the first week after hatching.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 58
    ISSN: 1432-0878
    Schlagwort(e): Olfactory-marker protein (OMP) ; Olfactory epithelium ; Immunocytochemistry ; Protein G-gold ; Freeze-substitution ; Lowicryl K11M embedding ; Rat (Sprague-Dawley)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary In this study electron-microscopic immunocytochemistry was used to localize olfactory marker protein in olfactory epithelia. Rat olfactory-epithelial samples were rapidly frozen, freeze-substituted with acetone, embedded at low temperatures with Lowicryl K11M and labelled on the sections with polyclonal antibodies raised against olfactory marker protein and with protein G conjugated to colloidal gold. Apart from the aforementioned use of acetone, substitution was carried out in the complete absence of chemical fixation, i.e., neither aldehydes nor OsO4 were used. This procedure resulted in localization concurrent with a good ultrastructural preservation. Olfactory-marker protein was present throughout the cytoplasmic compartments of dendrites and dendritic endings of olfactory-receptor cells, but it was not found in organelles such as mitochondria. Olfactory-marker protein was found only in dendriticendings of olfactory-receptor cells mature enough to have given rise to cilia, but these cilia displayed less labelling than dendrites and dendritic endings. Olfactory-marker protein was not found in apices and microvilli of neighboring olfactory-supporting cells.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 59
    ISSN: 1432-0878
    Schlagwort(e): Subcommissural organ ; Glial markers ; Immunocytochemistry ; GABA uptake ; Comparative analysis ; Mammals (rat, cat, mouse, rabbit)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The subcommissural organ (SCO), classified as one of the circumventricular organs, is composed mainly of modified ependymal cells, attributable to a glial lineage. Nevertheless, in the rat, these cells do not possess glial markers such as glial fibrillary acidic protein (GFAP), protein S100, or the enzyme glutamine synthetase (GS). They receive a synaptic 5-HT input and show pharmacological properties for uptake of GABA resembling the uptake mechanism of neurons. In this study, we examine the phenotype of several mammalian SCO (cat, mouse, rabbit) and compare them with the corresponding features of the rat SCO. In all these species, the SCO ependymocytes possess vimentin as an intermediate filament, but never express GFAP or neurofilament proteins. They do not contain GS as do glial cells involved in GABA metabolism, and when they contain protein S100 (rabbit, mouse), its rate is low in comparison to classical glial or ependymal cells. Thus, these ependymocytes display characteristics that differentiate them from other types of glial cells (astrocytes, epithelial ependymocytes and tanycytes). Striking interspecies differences in the capacity of SCO-ependymocytes for uptake of GABA might be related to their innervation and suggest a species-dependent plasticity in their function.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 60
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 257 (1989), S. 343-366 
    ISSN: 1432-0878
    Schlagwort(e): Central complex ; Golgi impregnation ; Neurotransmitters ; Protocerebrum, insect ; Immunocytochemistry ; Drosophila melanogaster (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary On the basis of 1200 Golgi-impregnated brains the structure of the central complex of Drosophila melanogaster was analyzed at the cellular level. The four substructures of the central complex — the ellipsoid body, the fanshaped body, the noduli, and the protocerebral bridge — are composed of (a) columnar small-field elements linking different substructures or regions in the same substructure and (b) tangential large-field neurons forming strata perpendicular to the columns. At least some small-field neurons belong to isomorphic sets, which follow various regular projection patterns. Assuming that the blebs of a neuron are presynaptic and the spines are postsynaptic, the Golgi preparations indicate that small-field neurons projecting to the ventral bodies (accessory area) are the main output from the central complex and that its main input is through the large-field neurons. These in turn are presumed to receive input in various neuropils of the brain including the ventral bodies. Transmitters can be attributed immunocytochemically to some neuron types. For example, GABA is confined to the R1–R4 neurons of the ellipsoid body, whereas these cells are devoid of choline acetyltransferase-like immunore-activity. It is proposed that the central complex is an elaboration of the interhemispheric commissure serving the fast exchange of data between the two brain hemispheres in the control of behavioral activity.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 61
    ISSN: 1432-0878
    Schlagwort(e): L1-antigen ; Cell adhesion molecule ; Developing vestibular neuroepithelium ; Immunocytochemistry ; Mouse (CBAxC57)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Doubts exist as to whether afferent nerve fibers exert a neurotrophic effect on the differentiation of sensory cells in the developing vestibular neuroepithelium. To determine whether innervation of hair cells precedes their differentiation, we have used the L1 adhesion molecule as a marker for axons. The detection of L1 on afferent axons in the otic vesicle of mouse embryos on gestation day 11 shows that nerve fibers penetrate the neuroepithelium before the sensory cells differentiate. L1-immunoreactivity of nerve endings also reveals the considerable fiber ramification on gestation days 14 and 15, i.e., corresponding to the first stages of sensory cell differentiation. The expression of L1 at successive stages of nerve fiber growth in the neuroepithelium, such as fasciculation and ramification, is not consistent with the previous role proposed for L1 as a fascicule-promoting factor and raises the possibility that other mechanisms are involved in L1 mediaded adhesion.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 62
    ISSN: 1432-0878
    Schlagwort(e): Neuropeptides ; Immunocytochemistry ; Lumbricus terrestris (Annelida, Oligochaeta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The localisation and distribution of 10 vertebrate-derived neuropeptides in the earthworm, Lumbricus terrestris, have been determined by an indirect immunofluorescence technique. The peptides are pancreatic polypeptide (PP), peptide tyrosine tyrosine (PYY), neuropeptide Y (NPY), glucagon (C-terminal), vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine (PHI), gastrinreleasing peptide (GRP), calcitonin gene-related peptide (CGRP), neurotensin (NT), and met-enkephalin. For 6 of the peptides — PYY, NPY, PHI, glucagon, GRP and CGRP — this is the first demonstration of their presence in any annelid, and NT has not previously been described in an oligochaete. Cell bodies and nerve fibres immunoreactive to the 10 peptides occur throughout the CNS. In the PNS, epidermal sensory cells displayed immunoreactivities to PP and PYY, and PP-, PYY-, NPY-, PHI- and GRP-like immunoreactivities occurred in nerve fibres supplying the main body muscles. Nerve fibres immunoreactive to PP and PYY are also associated with the innervation of the gut (pharynx, oesophageal glands, and mid and posterior regions of the intestine). No endocrine cells immunoreactive for any of the antisera tested could be identified in the gut epithelium, suggesting that dual location of peptides in the brain and gut epithelium is a phenomenon that occurred at a later stage in evolution. No immunoreactive elements were detected in any of the organs and ducts of the reproductive and excretory systems.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 63
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 255 (1989), S. 225-233 
    ISSN: 1432-0878
    Schlagwort(e): GABA ; Immunocytochemistry ; Visual system ; Optic lobes ; Periplaneta americana (Insecta)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Specific antisera against protein-conjugated γ-aminobutyric acid (GABA) were used in immunocytochemical staining procedures to study the distribution of the putative GABA-like immunoreactive neurons in the optic lobes of Periplaneta. GABA-like immunoreactive structures are evident in all three optic neuropil regions. Six different populations of GABAergic neurons, whose perikarya are grouped around the medulla, are found within the optic lobe. The number of these immunoreactive cells varies greatly and corresponds to the number of ommatidia of the eye. In the proximal part of the lamina, a coarse network of GABA-positive fibres is recognizable. These are the processes of large field tangential cells whose fibres pass through the distal surface of the medulla. A second fibre population of the lamina is made up of the processes of the centrifugal columnar neurons whose perikarya lie proximally to the medulla. The medulla contains 9 layers with GABAergic elements of variable immunoreactivity. Layers 1, 3, 5, 7 and 9 exhibit strong labelling, as a result of partial overlapping of the processes of centrifugal and centripetal columnar neurons, tangential fibres and/or lateral processes of perpendicular fibres and (possibly) processes of amacrines. A strong immunoreactivity is found in the proximal and distal layers of the lobula.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 64
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 257 (1989), S. 313-323 
    ISSN: 1432-0878
    Schlagwort(e): Serotonin (5HT) ; Immunocytochemistry ; 5,6-Dihydroxytryptamine ; Central nervous system ; Helix pomatia (Mollusca)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary The distribution of serotonin (5HT)-containing neurons in the central nervous system of the snail Helix pomatia has been determined in whole-mount preparations by use of immunocytochemical and in vivo 5,6-dihydroxy-tryptamine labelling. 5HT-immunoreactive neuronal somata occur in all but the buccal and pleural ganglia. Immunoreactive fibres are present throughout the central nervous system. The 5HT-immunoreactive neuronal somata characteristically appear in groups, located mainly in the cerebral, pedal, visceral and right parietal ganglia. The majority of 5HT-immunoreactive neurons is located in the pedal ganglia. Additionally a dense network of 5HT-immunoreactive varicose fibres is found in the neural sheath of the central nervous system including all the nerves and ganglia. The number and distribution of 5HT-immunoreactive neurons correlates with that demonstrated by 5,6-dihydroxytryptamine labelling method.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 65
    Digitale Medien
    Digitale Medien
    Springer
    Cell & tissue research 257 (1989), S. 545-548 
    ISSN: 1432-0878
    Schlagwort(e): Brush cells ; Fatty acid-binding protein ; Immunocytochemistry ; Stomach ; Rat (Wistar)
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary An immunocytochemical study by light- and electron microscopy using the antibody against rat hepatic fatty acid-binding protein (FABP) revealed the brush cells in the gastric epithelium of rats to be intensely immunoreactive. The immunoreactive cells were present in a group in the distal wall of the groove between forestomach and glandular stomach, as well as scattered singly in the surface and foveolar epithelia of the glandular stomach. Almost all immunoreactive brush cells had a thin basal process in contact with the basement membrane. No secretory granules with dense cores, similar to those of endocrine cells, were observed in the brush cells. The specific appearance of FABP-immunoreactivity in the brush cell indicates that this cell type is a distinct entity from other epithelial cells in the stomach and that FABP is a useful histochemical marker of the brush cells. FABP may be involved in the specific function(s) of this cell type related to fatty acid metabolism.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 66
    Digitale Medien
    Digitale Medien
    Springer
    Plant systematics and evolution 165 (1989), S. 227-237 
    ISSN: 1615-6110
    Schlagwort(e): Angiosperms ; Eucalyptus ; Eudesmieae ; Floral morphology ; calyx ; corolla ; operculum ; growth ; allometry ; convergence
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In theEudesmieae B eucalypts and inEucalyptus caesia, the perianth of the mature flower consists of a single, anatomically continuous, opercular structure that is crowned by the tips of the original free and separate calycine and corolline whorls. Ontogenetic and comparative evidence supports the hypothesis that this operculum is mostly corolline in composition, and that the calycine parts have been elevated distally onto the dorsal surface. In theEudesmieae B eucalypts this condition appears to be due to precocious initiation of the corolline primordia, followed by expansion and continuity of their growth centres which incorporates the areas at or below the base of the still differentiating calycine whorl. InEucalyptus caesia the corolline primordia are not precocious, but a similar situation is effected by a seemingly retarded increase in receptacle diameter relative to lateral expansion of the corolline growth centre(s). In these two examples the same final perianth form apparently derives from two different sets of growth processes which, nonetheless, result in the same allometric relationships within the developing flower. Although identical at maturity, the operculum form in these two taxa is best described in terms of convergence, rather than homology.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 67
    Digitale Medien
    Digitale Medien
    Springer
    Acta mechanica Sinica 5 (1989), S. 109-117 
    ISSN: 1614-3116
    Schlagwort(e): stability ; boundary layer ; compliant wall
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Physik
    Notizen: Abstract The stability characteristics of laminar boundary layers over compliant walls was studied by the linear theory. Unlike the previous authors, the coupled motion of the fluid and solid was required to satisfy the continuity conditions of both the velocity and stress at the interface. Results of calculations show that as the speed ratio or density ratio exceeds a certain threshold value, the two types of unstable waves will no longer be distinguishable, and the tangential component of the disturbance stress is no longer negligible. So the neglect of it, as the previous authors did, is unjustified.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 68
    ISSN: 1615-6102
    Schlagwort(e): Pyrenoid ; Ribulose 1,5-bisphosphate carboxylase/oxygenase ; Chlorella pyrenoidosa ; Immunocytochemistry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary The localization of ribulose 1,5-bisphosphate carboxylase/ oxygenase (RuBisCO) in cells ofC. pyrenoidosa grown at varying light intensities was determined by immunoelectron microscopy. Log phase cells grown at photon flux densities of 25 and 75 μEm−2s−1 (light-limiting) and 540 μEm−2s−1 (light-saturating) were fixed in 3% glutaraldehyde and embedded in Lowicryl K4M. Sections were labelled with antiserum to each subunit of RuBisCO followed by protein A-gold. At each light fluence rate, the pyrenoid was heavily labelled by each antibody whereas chloroplast stromal labelling was not above background levels. The apparent absence of stromal RuBisCO at each light level, and hence the lack of enzyme redistribution from pyrenoid to stroma following an increase in light fluence rate, suggests that pyrenoid RuBisCO is functional in vivo.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 69
    ISSN: 1573-5176
    Schlagwort(e): cyanobacteria ; blue-green algae ; biosynthesis ; growth ; gamma linolenic acid
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The total lipid and fatty acid content ofSpirulina platensis UTEX 1928 was 7.2 and 2.2% respectively of cellular dry weight under controlled conditions supporting high growth rates. With increases in irradiance from 170 to 870 μmol photon m−2 s−1, growth rate increased, total lipid decreased, and fatty acid composition was unaffected. At 1411 μmol photon m−2 s−1, total lipid increased slightly and percent composition of the fatty acid gamma linolenic acid increased. Growth and total lipid content ofS. platensis were affected by changes in growth temperature from 25 to 38 °C. With increased growth rate, total lipid content increased. This suggests that the storage of carbon increases at temperatures supporting high growth rates. The degree of saturation increased with temperature. Although the percent composition of gamma linolenic acid was higher at lower growth temperature, production was still primarily a function of growth rate. The effect of temperature on fatty acid content and degree of saturation was of secondary importance. Nitrogen starvation increased total lipid content but decreased fatty acid content as a percentage of dry weight; composition of the fatty acids was unaffected. N-starvation appeared to suspend synthesis of long chain fatty acids inS. platensis, suggesting that some other compound stores fixed carbon when nitrogen is limiting. It was concluded that fatty acid production inS. platensis is maximized by optimizing culture conditions for growth.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 70
    Digitale Medien
    Digitale Medien
    Springer
    Aquatic ecology 23 (1989), S. 73-83 
    ISSN: 1573-5125
    Schlagwort(e): model ; fish ; vegetation ; eutrophication ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A simple mathematical model was constructed, describing the relationships between pike, bream, aquatic macrophytes and the nutrient loading of shallow lakes. The model is analyzed with the use of zero-isoclines. It is concluded that, over a certain range of nutrient concentrations, the ecological relations incorporated in the model can give rise to the existence of two alternative stable equilibria;viz. a turbid bream-dominated one, and a clear state in which pike and aquatic vegetation are abundant. Under oligotrophic conditions, the clear-water state represents the only stable equilibrium; however, at high nutrient levels, the clear state is absent, or only locally stable. The response of the model to both increase and decrease of the nutrient level is characterised by hysteresis. The results indicate that manipulation of fish densities as a measure to improve water quality is only likely to produce long-term results when the nutrient level is below a certain threshold.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 71
    ISSN: 1573-5036
    Schlagwort(e): growth ; nutrition ; peanuts ; phosphorus ; VA mycorrhizae ; zinc
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Peanut plants (cv. Shulamit) were grown in an Oxisol soil in pots in the glasshouse to assess effects of soil sterilization and inoculation with spores of vesicular-arbuscular mycorrhizal fungi (VAMF) on the response to five rates of phosphorus (0 to 240 kg P ha−1) and two rates of zinc (0 and 10 kg Zn ha−1) fertilizers. Both P and Zn nutrition were affected by VAMF activity but the dominant role of VAMF in this soil type was in uptake of P. In the absence of VAMF there was a clear threshold level of P application (60 kg P ha−1) below which plants grew poorly, which resulted in a sigmoidal response of dry matter to applied P. The maximum response was not fully defined because dry matter production continued to increase up to 240 kg P ha−1. Tissue P concentration of non-mycorrhizal plants increased linearly with P rate and was always significantly less than that in mycorrhizal plants. Mycorrhizal plants responded without threshold to increasing P rate, attaining maximum dry matter at 120 kg P ha−1 in inoculated sterilized soil and at 30 kg P ha−1 in nonsterile soil. These differences in maximal P rates and in the greater dry matter produced in sterile soil at high P rates were attributed to the negative effects of the root-knot nematodeMeloidogyne hapla in nonsterile soil. Plant weight did not respond to zinc fertilizer but tissue Zn concentration increased with applied Zn. Tissue Zn concentration and uptake were increased by VAMF.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 72
    Digitale Medien
    Digitale Medien
    Springer
    Euphytica 44 (1989), S. 23-35 
    ISSN: 1573-5060
    Schlagwort(e): Solanum sp. ; Solanum tuberosum ; potato ; biomass production ; growth ; frost tolerance ; genetic variation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Plants grown from seed derived by crossing conventional European S. tuberosum material were compared with plants grown from seed derived by crossing S. tuberosum with various, Andean frost resistant tuberbearing Solanum species. Biomass growth at optimal (20°/10°) and suboptimal (10°/4°) temperatures was studied. Differences in increase of fresh and dry matter were found between populations of Andean and European orgins at 10°/4°. At 20°/10° no such differences were found. At suboptimal temperature, Andean hybrids produced significantly more fresh and dry matter than European crosses in two harvests (64 and 178 days old plants). Statistically, Andean hybrids were found to produce the same amount of dry matter per day at both temperatures, over the complete growth period. Height increase and flower development were strongly depressed in European crosses under the suboptimal temperatures, but much less so in Andean crosses. The Andean material appears to be an under utilized resource in potato breeding for cool climates.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 73
    ISSN: 1573-5060
    Schlagwort(e): Vigna radiata ; mungbean ; stability ; genotype-environment interaction ; wide adaptability ; AVRDC ; segmented regression
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Summary Yield data from the 5th–12th international mungbean nursery (IMN) trials conducted at 23 sites in 15 countries were analyzed by conventional stability analysis—regression of genotype mean on the environmental index, and by segmented regression analysis—fitting separate linear regressions in low yielding and high yielding environments. The gene pool base concept allows comparison of genotypes from different IMN trials grown in different years and sites. A very high positive linear relationship was observed between the regression coefficient and the average yield of cultivars, indicating that high yielding cultivars were less stable across environments. When data points of the regression of genotype mean and site mean for VC 1973A, a high yielding and widely adapted cultivar, were examined, the relationship appeared not to be linear. The segmented regression analysis improved the coefficient of determination (r2) and the genotypes were grouped based on regression coefficients in high yielding and low yielding environments. Different categories of genotypes suitable for high input environments, widely adaptable genotypes, and highly stable genotypes were identified.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 74
    Digitale Medien
    Digitale Medien
    Springer
    Plant growth regulation 8 (1989), S. 185-192 
    ISSN: 1573-5087
    Schlagwort(e): Mixtalol ; long chain alcohols ; Indian mustard ; Brassica juncea ; growth ; yield
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Mixtalol (a mixture of long chain aliphatic alcohols varying in chain length from C24 to C32) applied to Brassica juncea plants as foliar spray caused an increase in secondary and tertiary branching with consequent enhancement in seed yield through increased number of inflorescences and siliquae per plant. The percentage of immature siliquae and shattering of siliquae decreased with this treatment. Mixtalol increased total dry matter of plants, partitioning coefficient and harvest index. The contents of starch, protein and oil were also higher in seeds from Mixtalol treated plants.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 75
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 178 (1989), S. 193-198 
    ISSN: 1573-5117
    Schlagwort(e): diet ; growth ; flounder
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Many O-group flounder, Platichthys flesus, live in the lower reaches of rivers in North West Europe; while there is extensive information on the niche that they occupy in estuarine and marine environments, little is known of their life in freshwater. The diet of O-group flounder in the Lower Welsh River Dee was studied by stomach contents analysis of diel and seasonal samples. The dominant prey were chironomid larvae and pupae, tubificid oligochaetes and cyclopoid copepods. There was little quantitative variation in diet temporally, although a weak crepuscular pattern of stomach fullness was shown. There was wide variation in length and weight in all months, but the mean values at age I were 60 mm and 2.9 g respectively.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 76
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 188-189 (1989), S. 123-135 
    ISSN: 1573-5117
    Schlagwort(e): ecosystem stress ; fish populations ; growth ; fecundity ; condition factor
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The status of a fish population is a reflection of the overall condition of the aquatic environment in which that population resides. As such, fish population characteristics can be used as indicators of environmental health. Simple and inexpensive methods to follow fish population responses to environmental degradation are lacking. This paper outlines a protocol whereby environmental impacts on fish populations are classified by five patterns based on characteristics such as mean age, fecundity and condition factor. The patterns summarize population changes and describe responses to exploitation, recruitment failure, the presence of multiple stressors, food limitation and niche shifts. Classification is best based on the selection, and appropriate sampling, of a comparable reference population. Population characteristics can be used to examine ecosystems exposed to stressors for evidence of long-term damage, and when used with biochemical indicators, can be a powerful tool for ecosystem health assessment. The five responses are illustrated using published data on a number of species challenged by increased predation pressure, acidification, eutrophication, mine waste and reservoir impoundment. Application of this scheme will aid in directing and focusing research efforts on crucial aspects impacted by changing conditions.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 77
    ISSN: 1573-5117
    Schlagwort(e): Plecoptera ; Isoperla ; life cycles ; growth ; competition
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Studies on the life cycle and growth ofIsoperia grammatica andI. difformis from eight southern Swedish streams demonstrated that the former species shows greater between-stream differences than the latter species.I. grammatica larvae had typically two periods of rapid growth, autumn and spring, whileI. difformis larvae grew mainly in autumn-winter. In one of the streams, however,I grammatica grew rapidly throughout all winter. Maximum larval size differed between streams, and so did the timing of the first appearance of nymphs and nymphal maturation. Temperature was probably the most influential factor explaining all these differences. While sexual dimorphism inI. grammatica is slight but significant, it is very prominent inI. difformis. The sizes of larvae overlapped little between species as well as sexes suggesting that intra- and interspecific competition was, or had been, important. InI. grammatica this reduced overlap was expressed in several size-classes of males and females successively replacing each other, resulting in a meandering pattern of the size distribution charts. There were additional indications of possible interactions, such as a significant negative correlation between the densities of the two species.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 78
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 171 (1989), S. 159-170 
    ISSN: 1573-5117
    Schlagwort(e): Daphnia galeata mendotae ; Daphnidae ; Cladocera ; Crustacea ; cyclomorphosis ; phenotypic variability ; stability ; temperate lake ; coefficient of variation ; invertebrate predation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Phenotypic change is studied in a cyclomorphicDaphnia galeata mendotae population known from previous studies to be clonally diverse. Morphological analyses revealed cyclical changes in both adult and juvenile helmet length and tailspine length which were: 1) strongly correlated with mean water temperature; and 2) repeated annually during the 3-year study period. Field populations exhibited high (5% to 30%) coefficients of variation (CV) for both helmet length and tailspine length; the CV also exhibited seasonal fluctuations such that it was lowest in late summer. The period of highestDaphnia helmet development coincides with peak densities of the common invertebrate predatorsChaoborus andLeptodora. The fluctuations in CV may be due to both differential phenotypic expression of the coexisting clones and invertebrate predation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 79
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 171 (1989), S. 189-199 
    ISSN: 1573-5117
    Schlagwort(e): thermal structure ; heat content ; stability ; annual cycle ; diel variation ; tropical lakes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The thermal structure, heat content and stability were studied in Lakes Dom Helvécio and Carioca during an annual cycle. It was found that the maximum heat content, stability and work of the wind in Lake Dom Helvécio correspond to two, four and four times, respectively, the values for the Lake Carioca. These difference can be attributed to morphometric differences in the lakes. A long-term record of heat content and stability for lake Carioca is also presented. Diel variations were studied in summer and winter. The tropicality of the lakes is discussed and compared with other lacustrine systems.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 80
    Digitale Medien
    Digitale Medien
    Springer
    Hydrobiologia 174 (1989), S. 17-27 
    ISSN: 1573-5117
    Schlagwort(e): effects ; heavy metals (Cu, Zn) ; mayfly ; growth ; emergence ; indoor artificial streams
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Effects of Cu and Zn through food as well as through the water on the growth and emergence of the young larvae of Epeorus latifolium (Ephemeroptera), were investigated using an indoor model stream. The critical lowest concentrations of Cu which have significant effects on the growth of the larvae were between 10 and 15 µg l-1 Cu. Growth and emergence of the larvae fed on the algae (diatoms) which accumulated more than 1000 µg Cu g-1 (dry wt.) were significantly impaired. Growth of the mayfly larvae exposed to 100 or 300 µg l-1 Zn ceased after the second week, and all died before emergence. At 30 µg l-1 Zn, the growth rate decreased gradually and many larvae died before emergence. The molt interval also nearly doubled that of the control at these concentrations. Growth and emergence of the mayfly fed the algae which accumulated more than 2000 µg g-1 of Zn were significantly affected.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 81
    ISSN: 1573-5117
    Schlagwort(e): ammonium uptake ; carbon uptake ; chlorophyll a ; growth ; loss ; phytoplankton
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Daily changes of inorganic carbon and nitrogen uptake were measured in May in 1986 in Lake Nakanuma, Japan. Uptake of inorganic carbon and ammonium in the light-bottle experiments in the 1 m layers, showed daily changes similar to chlorophyll a changes, though the uptake activities peaked before chlorophyll a peaks (phytoplankton blooms) appeared. Potential growth rates of phytoplankton and observed growth rates were calculated from the uptake rates and chlorophyll a changes. The potential growth rates did not always correspond to the observed growth rates. The potential growth rates did not correlate with the loss rates. The correlation between the observed growth rates and the loss rates was better. These results suggest that though the increase of uptake activities may be necessary for occurrence of phytoplankton blooms, loss processes may affect the occurrence of blooms.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 82
    Digitale Medien
    Digitale Medien
    Springer
    Fish physiology and biochemistry 7 (1989), S. 395-405 
    ISSN: 1573-5168
    Schlagwort(e): endocrinology ; fish ; farming ; reproduction ; spawning ; sex control ; growth ; smoltification
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 83
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 118 (1989), S. 61-73 
    ISSN: 1573-5036
    Schlagwort(e): Alnus incana ; field ; Frankia ; growth ; intact plants ; nitrogenase activity ; nitrogen fixation ; photosynthesis
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The nitrogen-fixing grey alder,Alnus incana (L.) Moench, has a potential use in forest soil restoration and as part of energy forestry plantations. As a first step to estimate nitrogen fixation byA. incana under field conditions we performed studies on nitrogenase activity and its possible relation to abiotic factors and growth of the alders. Nitrogenase activity was measured as acetylene reduction activity (ARA) on eleven 1-year-old seedlings ofA. incana inoculated with a local source ofFrankia and planted in an experimental plot located in Umeå, northern Sweden. Each alder was planted into an open-ended cylinder which was closed with a gas tight lid around the stem base to serve as cuvette during ARA measurements. Propane served as tracer gas. ARA was measured in the middle of the day at 15 occasions during 26 June to 29 September 1987. Growth was recorded as leaf area and top shoot length at each ARA measurement until the end of August. Weather conditions were recorded for the whole growing season. Maximal ARA was recorded in late July or early August and ranged from 1.86 to 106μmol C2H4plant−1h−1. Final leaf area ranged from 0.022 to 0.124 m2. A relationship between ARA and the number of hours of sunshine during the same day was observed. ARA in relation to soil temperature increased during the study period, except for the last measurements. ARA in relation to leaf area was initially high but decreased later on. It is suggested that as leaves got older their contribution to photosynthesis per unit leaf area decreased and their potential to deliver nitrogen for retranslocation within plant increased. Both of these events would cause reduced ARA per unit leaf area. The data on ARA, growth, and abiotic factors taken together supported the view that sunshine and weather conditions affected photosynthesis and thereby delivery of assimilates to the nodules.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 84
    Digitale Medien
    Digitale Medien
    Springer
    Plant cell, tissue and organ culture 16 (1989), S. 89-102 
    ISSN: 1573-5044
    Schlagwort(e): Daucus carota ; suspension cultures ; 2-deoxy-D-glucose ; invertase ; sugars ; growth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Carrot (Daucus carota L.) cell suspension cultures grew well when provided with glucose, fructose, sucrose or raffinose. Galactose and melibiose supported less growth unless supplemented with glucose or fructose. In combination with ten different sugar mixtures, 2-deoxy-D-glucose (dGlc) inhibited culture growth. Inhibitory effects of dGlc were more marked with fructose, melibiose, raffinose or mixtures of these sugars in the culture medium. The presence of glucose or galactose reduced the inhibitory effects of dGlc on culture growth. Experiments with radioactive labelled sugars demonstrated that dGLc uptake was greater in the presence of fructose than glucose, and that growth inhibition of dGlc coincided with its uptake. Reduced protein content was also associated with the inhibitory effects of dGlc. Cultured cells contained lower levels of invertase (EC 3.2.1.26) activity during the active phase of culture growth (up to 25 days after subculture) than when growth had peaked and subsequently declined. Acid and alkaline invertase activities were not greatly reduced by exogenous hexoses. Invertase activity was greatest during periods of low protein content in all cultures and was inhibited by dGlc during the latter phases of the culture period. Free intracellular sugars throughout the culture period consisted mainly of glucose and fructose.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 85
    Digitale Medien
    Digitale Medien
    Springer
    Fish physiology and biochemistry 6 (1989), S. 11-18 
    ISSN: 1573-5168
    Schlagwort(e): skeleton photoperiod ; smolt ; endogenous rhythm ; growth ; osmoregulation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract Underyearling coho salmon fry were subjected to three initial photoperiod treatments (6L∶18D, 10L∶14D, 14L∶10D) for two months and subsequently to three final treatments (16L∶8D, 9L∶6D∶1L∶8D, 10L∶14D) in a factorial design. Growth rates and seawater adaptability were monitored regularly. The groups that were exposed initially to 6L∶18D or 10L∶14D and then to 16L∶8D grew faster and had lower plasma sodium ion levels after seawater challenge tests than any of the other groups. Fish which were initially exposed to 6 L or 10 L daylength and then to a 9L∶6D∶1L∶8D skeleton photoperiod, showed a slightly lower growth rate and seawater adaptability than those given the corresponding complete 16L∶8D photoperiod. However fish maintained on skeleton photoperiods had significantly greater growth rates and seawater adaptability than those kept on the 10L∶14D photoperiod. This indicates that it is not the accumulated number of hours of exposure to light that initiates smolting, but rather the time during the day when light is experienced. Fish exposed initially to 14L∶10D showed little or no response to subsequent changes in photoperiod, suggesting that responsiveness to inductive photoperiods depends on the initial photoperiod treatment.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 86
    Digitale Medien
    Digitale Medien
    Springer
    Fish physiology and biochemistry 7 (1989), S. 49-58 
    ISSN: 1573-5168
    Schlagwort(e): fish ; endocrinology ; reproduction ; hypophysation ; growth ; stress ; behavior ; fish culture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract In the current practice of fish culture the use of hormones is mainly limited to the field of reproduction, and more precisely to induce or synchronize ovulation and stimulate spermiation. The practice of pituitary homogenates injection (called hypophysation) which started in the early 1930's has allowed spectacular developments in the culture of some cyprinid species, especially in China, India and Europe. HCG has been used successfully in a limited number of species and LHRH-A, often associated with antidopaminergic compounds, started to be used in some species, especially cyprinids, on a commercial scale. Sex steroids are now commonly used to reverse the sex of some species in salmonids, cyprinids, tilapias. Due to legal restriction and consumer opposition, the tendency is to limit the use of steroids, especially in fish which are later offered to consumption. GH, which significantly stimulates growth and reduces the food conversion rate in laboratory experiments, will possibly be used on a large scale in fish farms. Endocrinology has considerably increased the knowledge of the mechanisms controlling some physiological functions; this has allowed the identification of sensitive phases in fish in captivity, and helps in the management and the process of domestication (most of the cultured fish species have been taken form the wild recently).
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 87
    Digitale Medien
    Digitale Medien
    Springer
    Fish physiology and biochemistry 6 (1989), S. 113-120 
    ISSN: 1573-5168
    Schlagwort(e): growth ; endocrinology ; reproduction ; triploid ; salmonid ; sterilization ; aquaculture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract This paper describes the effect of triploidy on growth and reproductive endocrinology in the months leading up to and including spawning in rainbow trout,Salmo gairdneri, and pink salmon,Oncorhynchus gorbuscha. Growth rates were the same for diploid and triploid rainbow trout, but triploid female pink salmon were smaller than maturing diploid females and diploid and triploid males of the same age. Triploid males of both species developed typical secondary sexual characteristics and had normal endocrine profiles, although their cycle appeared to be delayed by about one month. Triploid females remained silvery in appearance and showed no endocrine signs of maturation, even at the level of the pituitary. Thus, although triploids of both sexes are genetically sterile, only the females do not undergo physiological maturation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 88
    ISSN: 1573-5168
    Schlagwort(e): carp ; anabolic-androgenic steriods ; growth ; tissue RNA/DNA ratios
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A study on the effect of three different anabolic-androgenic steroids on the growth, food conversion efficiency and nucleic acid contents of liver, kidney, brain and muscle of carp,Cyprinus carpio was undertaken. The three steroids, methyltestosterone (MT), ethylestrenol (EE) and oxandrolone (ON), were fed in different combinations at final concentrations of 5 or 6 mg/kg diet for 60 days. No effect on the growth was observed in any of the experimental groups. A decrease in the specific growth rate (11–21%) and food conversion efficiency (20–29%) was noted. Feeding of drugs increased the cranio-somatic and reno-somatic index in all except one group. Hepatosomatic (ON+MT) and viscero-somatic (ON+MT; EE+MT+ON) indices decreased. Protein increased and RNA/DNA decreased in only one group while a decrease in protein/DNA was observed in the liver of all experimental groups. RNA/DNA increased and protein/RNA decreased only in one group while no effect was seen in protein and protein/DNA contents in any of the treated kidneys. Proteins, protein/RNA and protein/DNA decreased in certain groups in brain tissue. In muscle, no effect was seen in proteins or protein/DNA. Protein/RNA decreased in all but one group while RNA/DNA was higher only in the group fed all the three steroids together.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 89
    ISSN: 1573-1561
    Schlagwort(e): European corn borer ; Ostrinia nubilalis ; Lepidoptera ; Pyralidae ; corn ; DIMBOA ; 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one ; tritiated DIMBOA ; toxicokinetics ; topical application ; body burden ; growth
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract 2,4-Dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA), the major hydroxamic acid present in corn, and its tritiated derivative, were prepared synthetically for use in the determination of the toxicokinetics of this insect deterrent in the European corn borer (ECB),Ostrinia nubilalis. In growth studies with DIMBOA (0, 0.05, 0.2, and 0.5 mg/g diet), the mean time to pupation and adult emergence were significantly lengthened by an increase in concentration. Pupal and adult weights, for both female and male, decreased with an increase in concentration. Increased larval and pupal mortality occurred at the highest concentration of DIMBOA. DIMBOA, at concentrations of 0.2 and 0.5 mg/g diet, resulted in a decrease in the number of egg masses produced per female, and at 0.5 mg/g diet, in a decrease in the number of eggs per egg mass. Larvae fed from the neonate stage on a diet containing 0.2 mg [3H]- + [1H]DIMBOA/g diet showed an increase in the content of label from fourth to fifth instar, but levels declined at pupation and emergence. A large amount of the labeled compounds was excreted by the insect in the pupal case. In dose-related studies, both uptake and excretion increased with an increase in concentration of DIMBOA (0.05, 0.2, 0.4 mg/g diet), while a body burden (concentration in the tissues/concentration in the frass) of approximately 0.25 was maintained for all concentrations. At the highest dose of DIMBOA (0.4 mg/g), the ECB increased consumption, possibly to compensate for the toxic effects of the compound. In topical application studies, elimination of the labeled compound in the frass was rapid, reaching 65% by 4 hr and 88% by 48 hr. Accumulation of label in tissues other than hemolymph was low. The results show that the ECB does possess adaptive mechanisms to deal with the effects of this host-derived compound.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 90
    Digitale Medien
    Digitale Medien
    Springer
    Rheologica acta 28 (1989), S. 504-510 
    ISSN: 1435-1528
    Schlagwort(e): Taylor-Couette flow ; stability ; Doi-Edwards equation ; inertia
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Abstract The stability of Taylor-Couette flow of entangled polymeric solutions to small axisymmetric stationary disturbances is analyzed using the Doi-Edwards constitutive equation in the small gap limit. A previous analysis of Karlsson, Sokolov, and Tanner for the general K-BKZ equation, of which the Doi-Edwards equation is a special case, reduces the problem to one of numerically evaluating seven viscoelastic functions of the shear rate $$\dot \gamma$$ in the gap. Of these seven, only three — two of which are related to the second normal stress difference, and one of them to shear thinning — significantly affect the flow stability. The negative second normal stress difference of the Doi-Edwards fluid stabilizes the flow at low values of the Weissenberg number λ1 $$\dot \gamma$$ , while shear thinning produces strong destabilization at moderate Weissenberg number. Hereλ 1 is the longest relaxation time. Non-monotonic effects of viscoelasticity on Taylor-Couette stability analogous to those predicted here have been observed in experiments of Giesekus. The extreme shear thinning of the Doi-Edwards fluid is also predicted to produce a large growth in the height of the Taylor cells, a phenomenon that has been seen experimentally by Beavers and Joseph.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 91
    Digitale Medien
    Digitale Medien
    Springer
    Rheologica acta 28 (1989), S. 499-503 
    ISSN: 1435-1528
    Schlagwort(e): Taylor-Couetteflow ; stability ; Boger fluid ; Oldroyd-B equation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Physik
    Notizen: Abstract Experimental evidence of a non-inertial, cellular instability in the Taylor-Couette flow of a viscoelastic fluid is presented. A linear stability analysis for an Oldroyd-B fluid, which is successful in describing many features of the experimental fluid, predicts the critical Deborah number,De c , at which the instability is observed. The dependence ofDe c on the value of the dimensionless gap between the cylinders is also determined.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 92
    Digitale Medien
    Digitale Medien
    Springer
    Acta applicandae mathematicae 14 (1989), S. 125-133 
    ISSN: 1572-9036
    Schlagwort(e): 92A07 ; stationary solution ; immune response ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Some results connected with a simple mathematical model of infectious disease are discussed in order to demonstrate the approach to the modelling of such real processes. A more complicated model of antiviral immune response is presented. A new modification of this model in which targets for the viruses are immunocompetent cells is suggested.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 93
    Digitale Medien
    Digitale Medien
    Springer
    Acta applicandae mathematicae 15 (1989), S. 211-234 
    ISSN: 1572-9036
    Schlagwort(e): 70F99 ; 70K20 ; 73C02 ; 35P30 ; Flexible body ; Lagrangian and Hamiltonian dynamics ; stability ; partial differential equations
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract We analyse here the equations of motion of a planar body consisting of a rigid body with attached flexible rod. These equations take the form of coupled ordinary and partial differential equations. We analyse the equations both with and without centrifugal stiffening effects. Using the ‘energy-momentum’ method, we analyse nonlinear stability of the equilibria in each case. We also analyse the Hamiltonian and Poisson bracket structure of the system as well as the energy-momentum map and associated relative equilibria.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 94
    Digitale Medien
    Digitale Medien
    Springer
    Journal of statistical physics 56 (1989), S. 533-545 
    ISSN: 1572-9613
    Schlagwort(e): Immune system ; dormant B cells ; cycles ; Jerne theory ; memory ; nonlinear phenomena ; stability
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract The role of dormant B cells and cycles is analyzed in the context of a Lotka-Volterra network. It is shown that dormant B cells stabilize a cycle and that in this way both cooperate to preserve the internal image (memory) of an antigen. The network is embedded in a hierarchical scheme which allows adaptation, learning, and innovation by biased and random mutation.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 95
    Digitale Medien
    Digitale Medien
    Springer
    Journal of comparative physiology 159 (1989), S. 237-242 
    ISSN: 1432-136X
    Schlagwort(e): Amylase ; Mosquitofish ; Rat ; Drosophila ; Structure ; Function
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Summary Amylases from the mosquitofish (Gambusia affinis holbrooki, Pisces: Poeciliidae) and rat were purified and compared withDrosophila amylases in terms of structure and function. At the structural level, amino acid compositions of the three amylases were compared. At the functional level, amylase activities were compared on various substrates and in the presence of inhibitors. While the amylases from all three organisms had properties typical of alpha-amylases, both structural and functional differences were observed. Using resemblance coefficients of distance and similarity from numerical taxonomy, it was determined that the amylases from the rat andDrosophila were more similar to each other than either was to amylase from the mosquitofish, and that structural differences between the amylases did not reflect functional differences, i.e. there was no correlation between amylase structural and functional distances.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 96
    Digitale Medien
    Digitale Medien
    Springer
    Pharmaceutical research 6 (1989), S. 971-975 
    ISSN: 1573-904X
    Schlagwort(e): lyophilization ; stability ; pH effect ; moexipril
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Notizen: Abstract Because of the limited stability of moexipril (RS-10085; 1) in aqueous solution, lyophilized parenteral formulations were evaluated as a function of pH in this study. In general, the lyophilized powder of 1 showed about two orders of magnitude less reactivity at 50°C than in aqueous solution at pH values below 3 or above 6. At pH 5.1, however, the lyophilized powder had maximum reactivity, with the rate actually comparable to that observed in aqueous solution. When the distribution of the two major products, diketopiperazine (DKP) 2 and ester hydrolysis analogue 3, was compared to the observed kinetics as a function of pH, it was clear that removal of water via lyophilization suppressed the spontaneous k 1 cyclization process, the spontaneous k 3 hydrolysis process, and the specific base-catalyzed k 4 hydrolysis process. The overall spontaneous k 2 cyclization process, however, was not affected by lyophilization. The latter result is accounted for by the increased equilibrium constant for the formation of the tetrahedral intermediate, To, as a result of lyophilization. This study demonstrates that stability data in solution can not be used for predicting the stability of moexipril in lyophilized powder form.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 97
    Digitale Medien
    Digitale Medien
    Springer
    Journal of optimization theory and applications 63 (1989), S. 79-89 
    ISSN: 1573-2878
    Schlagwort(e): Probabilistic constrained programs ; feasible solution sets ; stability ; point-to-set maps
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract In this paper, we show the continuity of the feasibility set with respect to the reliability levels and with respect to the distribution of the random elements of a stochastic program with probabilistic constraints. Continuity is then used to obtain stability results for this type of stochastic program. An easy criterion is given for checking the conditions which guarantee the continuity of the feasibility set.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 98
    Digitale Medien
    Digitale Medien
    Springer
    Journal of optimization theory and applications 61 (1989), S. 73-94 
    ISSN: 1573-2878
    Schlagwort(e): Decentralized control ; stabilization by output feedback ; stability ; numerical methods ; discrete-time linear systems
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract In this paper, we present an approach for designing structural constrained controllers for discrete-time linear systems, based on a new stabilizability property of the Riccati equation solution. First, the feedback stabilization problem under a general structural constraint is considered and a simple numerical procedure to solve it is presented. Special attention is given to the output feedback stabilization problem, for which sufficient conditions for the existence and convergence toward a stabilizing matrix are provided. Some examples are solved and comparisons with other methods available in the literature are made.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 99
    Digitale Medien
    Digitale Medien
    Springer
    Journal of optimization theory and applications 61 (1989), S. 403-408 
    ISSN: 1573-2878
    Schlagwort(e): Isoperimetric inequalities ; stability ; circular rings ; structural optimization
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract The problem of determining the optimal cross section of a circular ring so as to maximize the buckling pressure under a given total volume is formulated and solved. An isoperimetric inequality is proved: Among all the circular rings of given mass and radius, the ring with constant bending rigidity along the arc length has the largest critical buckling pressure.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
  • 100
    Digitale Medien
    Digitale Medien
    Springer
    Journal of optimization theory and applications 62 (1989), S. 419-447 
    ISSN: 1573-2878
    Schlagwort(e): Minimax optimization ; parametric optimization ; transversality ; sensitivity ; stability ; Chebyshev approximation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract We consider functions of maximum type (max functions for short), subject to (in)equality constraints. The space dimension is finite, and the maximum is taken over a compact manifold with boundary. Effective local minimization algorithms based on Newton's method can be derived in the case where a local minimum is nondegenerate (in a two-level sense). In fact, nondegeneracy refers on the one hand to a local (implicit) reduction of the original max function to another one, where the maximum is taken over a finite set. On the other hand, it refers to strict complementarity and nondegeneracy of the underlying quadratic form with respect to the reduced stationary situation. As the main goal, we show that the set ofn-parameter families of functions, for which the stationary points of the corresponding max function are nondegenerate, constitutes an open and dense subset in the space of alln-parameter families (the topology used takes derivatives up to second order into account). An application to approximation problems of Chebyshev type is presented.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
    BibTip Andere fanden auch interessant ...
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...