ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • 1985-1989  (3)
  • 1975-1979  (6)
  • 1
    Publication Date: 1986-12-01
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 1977-01-01
    Print ISSN: 0949-944X
    Electronic ISSN: 1432-041X
    Topics: Biology
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 1977-01-01
    Print ISSN: 0949-944X
    Electronic ISSN: 1432-041X
    Topics: Biology
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Publication Date: 1977-01-01
    Print ISSN: 0949-944X
    Electronic ISSN: 1432-041X
    Topics: Biology
    Published by Springer
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 183 (1977), S. 193-206 
    ISSN: 1432-041X
    Keywords: Hydra mutant ; Morphogenetic substances ; Head formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A mutant ofHydra attenuata is analysed, theaberrant, which is distinct from the wild type in having a smaller head with fewer tentacles and only half the number of head-specific cells. The rate of head and foot regeneration and the doubling time are slower inaberrants than in normal hydra. The lower head-forming potential is paralleled by a reduced concentration of head-specific morphogens: compared to the wild type, in theaberrant the concentration of head activator is reduced to 70% in the head and to 50% in the body, the concentration of head inhibitor is reduced to 50% in the head and to 80% in the body. Theaberrant is more sensitive (3 times) to added head activator and less sensitive (〉5 times) to added head inhibitor than the wild type. The slower rate of foot regeneration is paralleled by a lower content of foot-specific morphogens: compared to the wild type, in theaberrant the foot activator is reduced to 40% and the foot inhibitor to 70%.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 183 (1977), S. 207-214 
    ISSN: 1432-041X
    Keywords: Hydra mutant ; Morphogenetic substances ; Bud formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Non-budding mutants ofChlorohydra viridissima regenerate heads 6 h faster thanHydra attenuata and the number of tentacles per head is higher. The polarity in pieces from the gastric region is the more labile, the smaller the pieces are. In regenerates heads and tentacles form much more frequently than feet, giving rise to bipolar or multiheaded structures. Buds very seldom form under normal conditions, but they occasionally occur in regenerating animals with two cut surfaces. The higher head-forming potential in the mutant is paralleled by a higher head-activator concentration (20-fold in head, 4-fold in body), than inHydra attenuata, which is not accompanied by an equivalent increase in head-inhibitor concentration (1.4-fold in head, 2-fold in body). The foot-activator concentration is slightly reduced (1.3-fold), the foot-inhibitor concentration is higher (1.6-fold) than inH. attenuata. The mutant is extremely insensitive to head activator, relatively insensitive to head inhibitor and foot inhibitor, but sensitive to foot activator.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Development genes and evolution 183 (1977), S. 215-222 
    ISSN: 1432-041X
    Keywords: Hydra mutants ; Morphogenetic substances ; Size regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Minis have a doubling time of 2.4 days,maxis of 8 days.Minis regenerate head and foot 5 h faster thanmaxis.Minis have fewer tentacles (4.6) per head thanmaxis (6.1). Inmini the concentration of the head activator is equal to that inHydraattenuata, but the concentration of the head inhibitor is reduced (2-fold in the head, 1.2-fold in the body). The concentrations of the foot factors are normal.Minis respond likeHydra attenuata to head activator, foot activator and foot inhibitor, but they are less sensitive to head inhibitor Inmaxi the concentration of the head activator is higher than inmini (5-fold in the head, 10-fold in the body) and that of the head inhibitor is also higher (4-fold in the head, 5-fold in the body). The concentration of the foot inhibitor is normal, that of the foot activator is doubled.Maxis are insensitive to added head activator and less sensitive to added head inhibitor and foot inhibitor. Their response to foot activator is normal.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 241 (1985), S. 171-182 
    ISSN: 1432-0878
    Keywords: RFamide ; Neuropeptides ; Nervous system ; Reproduction ; Hydrozoa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Antisera to the sequence Arg-Phe-amide (RF-amide) have a high affinity to the nervous system of fixed hydroid polyps. Whole-mount incubations of several Hydra species with RFamide antisera visualize the three-dimensional structure of an ectodermal nervous system in the hypostome, tentacles, gastric region and peduncle. In the hypostome of Hydra attenuata a ganglion-like structure occurs, consisting of numerous sensory cells located in a region around the mouth opening and a dense plexus of processes which project mostly radially towards the bases of the tentacles. In Hydra oligactis an ectodermal nerve ring was observed lying at the border of hypostome and tentacle bases. This nerve ring consists of a few large ganglion cells with thick processes forming a circle around the hypostome. This is the first direct demonstration of a nerve ring in a hydroid polyp. Incubation of Hydractinia echinata gastrozooids with RFamide antisera visualizes an extremly dense plexus of neuronal processes in body and head regions. A ring of sensory cells around the mouth opening is the first group of neurons to show RFamide immunoreactivity during the development of a primary polyp. In gonozooids the oocytes and spermatophores are covered with strongly immunoreactive neurons. All examples of whole-mount incubations with RF-amide antisera clearly show that hydroid polyps have by no means a “diffuse nerve net”, as is often believed, and that neuronal centralization and plexus formation are common in these animals. The examples also show that treatment of intact fixed animals with RFamide antisera is a useful technique to study the anatomy or development of a principal portion of the hydroid nervous system.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 246 (1986), S. 463-479 
    ISSN: 1432-0878
    Keywords: RFamide ; Neuropeptide ; Nervous system ; Siphonophores ; Coelenterates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An antiserum to the sequence Arg-Phe-amide (RFamide) was used to stain the nervous systems of various physonectid siphonophores. In the stem of Nanomia bijuga, this antiserum stained an ectodermal nerve net, which was interrupted, at regular intervals, by transverse collars of neurons. Injection of Lucifer yellow into the “giant axon” of the stem showed that this axon was dye-coupled to an ectodermal nerve net that resembled the RFamide-positive network. Ectodermal nets of neurons were also found in the pneumatophore, gastrozooids, tentacles and tentilla. At the junctions of the pneumatophore, the gastrozooids, the dactylozooids and the gonozooids with the stem, and at the junctions of tentacles and tentilla, collars or rings of neurons occurred. The stem was connected to the phyllozooids and nectophores by muscular lamellae, which were bordered by chains of neurons. At the margin of the nectophores, an immunoreactive nerve ring was found. Connected to this ring and located in the“seitliche Zapfen” (“sidely-located patche”), were two agglomerations of nerve cells. On the upper side of the bell margin, positioned at 90° relative to the “seitliche Zapfen”, a delta-shaped neuronal structure was found. This structure was connected to the nerve ring and was associated with a muscle, which ran a short distance along the exumbrellar surface. The nervous systems of Agalma elegans, Forskalia edwardsi, Forskalia leuckarti and Halistemma rubrum resembled that of Nanomia bijuga in all major respects.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...