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1

Electronic Resource

Analysis of morphogenetic mutants of hydra (1977)

Schaller, H. C. ; Schmidt, T. ; Flick, K. ; [et al.]

Springer

Development genes and evolution 183 (1977), S. 193-206

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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

URL: http://dx.doi.org/10.1007/BF00867320

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2

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Analysis of morphogenetic mutants of hydra (1977)

Schaller, H. C. ; Schmidt, T. ; Flick, K. ; [et al.]

Springer

Development genes and evolution 183 (1977), S. 215-222

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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

URL: http://dx.doi.org/10.1007/BF00867322

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3

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Analysis of morphogenetic mutants of hydra (1977)

Schaller, H. C. ; Schmidt, T. ; Flick, K. ; [et al.]

Springer

Development genes and evolution 183 (1977), S. 207-214

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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

URL: http://dx.doi.org/10.1007/BF00867321

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4

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A neurohormone from hydra is also present in the rat brain (1975)

Schaller, H. C.

Oxford, UK : Blackwell Publishing Ltd

Journal of neurochemistry 25 (1975), S. 0

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ISSN: 1471-4159

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Medicine

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1111/j.1471-4159.1975.tb12249.x

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5

Electronic Resource

Epithelial cells in nerve-free hydra produce morphogenetic substances (1980)

Schaller, H. C. ; Rau, T. ; Bode, H.

[s.l.] : Nature Publishing Group

Nature 283 (1980), S. 589-591

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ISSN: 1476-4687

Source: Nature Archives 1869 - 2009

Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics

Notes: [Auszug] In a preliminary investigation we have shown that severely nerve-depleted hydra, which consist almost exclusively of epithelial cells, contain normal concentrations of morphogenetic substances7. To exclude the possibility that the few remaining nerve cells overproduce these substances, we have ...

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1038/283589a0

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Elevated levels of head activator in human brain tumors and in serum of patients with brain and other neurally derived tumors (1988)

Schaller, H. C. ; Schilling, E. ; Theilmann, L. ; [et al.]

Springer

Journal of neuro-oncology 6 (1988), S. 251-258

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ISSN: 1573-7373

Keywords: neuropeptide head activator ; brain-tumor marker

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine

Notes: Abstract In normal human tissue high concentrations of the neuropeptide head activator are found in the hypothalamus, in the retina, and in the gastro-intestinal tract. Up to 100-fold elevated levels of head activator over neighbouring tissue were found in tumors of the brain, especially in tumors of neural origin like astrocytoma and glioblastoma, but also in meningioma. Coincident with elevated tissue levels, an increased secretion into the general circulation was observed. Elevated levels of head activator in the blood were also observed in patients with tumors in peripheral locations, especially in tumors of gastrointestinal tract and/or of neuroendocrine origin. After tumor removal, the head activator levels in the blood dropped to normal values suggesting a possible role of head activator in neuroendocrine tumorigenesis.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00163709

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7

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Expression and characterization of the ”laminin binding protein” in hydra (1997)

Keppel, E. ; Fenger, U. ; Schaller, H. C.

Springer

Cell & tissue research 287 (1997), S. 507-512

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ISSN: 1432-0878

Keywords: Key words: Laminin binding protein (LBP) ; Rapidly cycling cells ; CDC2 kinase ; Cytoplasmic localization ; Hydra vulgaris (Cnidaria) ; Chlorohydra viridissima (Cnidaria)

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Abstract. Recently, a cDNA was isolated from hydra with extensive homology to a mammalian and invertebrate gene which codes for a protein called laminin binding protein (LBP). In this paper we describe the protein expression of the hydra LBP in Escherichia coli. On SDS gels the recombinant hydra LBP displayed an apparent molecular mass of 43 kDa, although the calculated mass, including six additional histidines, is 33.7 kDa. Polyclonal antibodies were produced against the hydra recombinant LBP. The antiserum reacted with a 42-kDa and a 43-kDa protein from Hydra vulgaris and from a multiheaded mutant of Chlorohydra viridissima, respectively. In hydra, LBP RNA and protein were highly expressed in cells with short cell cycles, such as all cells of the interstitial cell lineage, less in slowly cycling epithelial cells, and at very reduced levels or not at all in differentiated cells. Higher expression in the multiheaded mutant of C. viridissima than in H. vulgaris, the cells of which differ in doubling time, hint at a function in cell proliferation. This is supported by the finding that in vitro hydra LBP is a substrate for the cell-cycle-specific kinase CDC2.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s004410050774

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