Genetic analysis of developmental mechanisms in hydra

A mutant strain (nf-I) of Hydra magnipapillata was isolated that contained no interstitial cells, nerve cells or nematocytes. This strain appeared spontaneously in a sexually inbred clone of hydra, and it was recognized by its inability to eat. When force-fed, however, it grew, multiplied by budding and regenerated. In this and in many other respects, nf-I was very similar to the interstitial cell-deficient strain produced by Campbell (1976) by means of colchicine. A chimera strain was produced by the reintroduction of interstitial cells from another strain into nf-I. The properties of nf-I, the chimera and other related strains were examined, and the possible roles that the interstitial cells and the nerve cells play in growth and morphogenesis of hydra are discussed.

Download Full-text

Genetic analysis of developmental mechanisms in hydra

Developmental Biology ◽

10.1016/0012-1606(85)90371-9 ◽

1985 ◽

Vol 107 (1) ◽

pp. 13-27 ◽

Cited By ~ 25

Author(s):

Josef Achermann ◽

Tsutomu Sugiyama

Keyword(s):

Genetic Analysis ◽

Developmental Mechanisms

Download Full-text

Genetic analysis of developmental mechanisms in hydra

Development ◽

10.1242/dev.42.1.65 ◽

1977 ◽

Vol 42 (1) ◽

pp. 65-77

Author(s):

Tsutomu Sugiyama ◽

Toshitaka Fujisawa

Keyword(s):

Epithelial Cells ◽

Genetic Analysis ◽

Mutant Strain ◽

Interstitial Cells ◽

Nerve Cells ◽

Abnormal Development ◽

Wild Type ◽

Developmental Mechanisms ◽

Head Formation

Mutant hydra strains showing abnormal development can be isolated through sexual inbreeding of wild hydra. One such mutant strain, called reg-16, regenerates tentacles very poorly following amputation of the head and foot. Tentacle regeneration, however, is significantly enhanced by subdividing the regenerating fragment longitudinally. Lateral tissue implants that induce head formation in wild-type hydra either regress or induce foot formation in reg-16 polyps. These results suggest that regeneration deficiency in reg-16 is due to a defective polarity gradient. A chimaeric strain of hydra was produced by combining interstitial cells (and thus their differentiation products, nerve cells and nematocytes) of reg-16 hydra with epithelial cells of another strain which is capable of normal regeneration. The chimaeras regenerate normally, suggesting that the defect of reg-16 is not located in the interstitial or nerve cells.

Download Full-text

Genetic analysis of developmental mechanisms in hydra. VIII. Head-activation and head-inhibition potentials of a slow-budding strain (L4)

Development ◽

10.1242/dev.78.1.141 ◽

1983 ◽

Vol 78 (1) ◽

pp. 141-168 ◽

Cited By ~ 1

Author(s):

Jun Takano ◽

Tsutomu Sugiyama

Keyword(s):

Pattern Formation ◽

Genetic Analysis ◽

Structure Formation ◽

Tissue Transplantation ◽

Normal Strain ◽

Polyp Size ◽

Developmental Mechanisms ◽

Head Formation ◽

Lower Head ◽

Activation Potential

Morphogenetic potentials involved in head formation were examined in a hydra strain (L4) which has a very low budding rate and a large polyp size, and the results were compared to those of the normal strain (105). Hydra tissue has two types of antagonistic morphogenetic potentials which are thought to play important roles in head structure formation: the head-activation potential and the head-inhibition potential. Lateral tissue transplantation (Webster & Wolpert, 1966) was used to compare the levels of the two potentials in L4 and the normal strain. It was found that the intact polyp of L4 has a nearly normal or slightly lower head-activation potential but a significantly higher head-inhibition potential than the normal strain. During the course of regeneration after head amputation, the levels of the two potentials in L4 changed in significantly different patterns from those in the normal strain. These abnormalities of the two potentials may be responsible for the developmental and morphological abnormalities in L4. The significance of these observations is discussed in light of the current hydra pattern formation models (Wolpert, Hornchurch & Clarke, 1974; Meinhardt & Gierer, 1974).

Download Full-text

Genetic analysis of developmental mechanisms in hydra. VI. Cellular composition of chimera hydra

Journal of Cell Science ◽

10.1242/jcs.35.1.1 ◽

1979 ◽

Vol 35 (1) ◽

pp. 1-15

Author(s):

T. Sugiyama ◽

T. Fujisawa

Keyword(s):

Epithelial Cell ◽

Genetic Analysis ◽

Interstitial Cell ◽

Cell Types ◽

Interstitial Cells ◽

Cellular Composition ◽

Feedback Mechanisms ◽

Cell Lineages ◽

Developmental Mechanisms ◽

Homeostatic Mechanisms

The homeostatic mechanisms that maintain constant cellular ratios in hydra tissue were studied using mutant and chimeric hydra strains. Mutants having abnormal cellular compositions are isolated through sexual inbreeding of wild hydra, as described in previous papers of this series. Chimeric hydra are produced by making use of a strain (nf-I) which lacks interstitial cells, nerve cells and nematocytes in its tissue. Reintroduction of interstitial cells from other strains (both normal and mutant) into nf-I leads to creation of chimeric strains having epithelial cell lineages from one strain (nf-I) and interstitial cell lineages from others. Analyses and comparisons of the cellular compositions of all these strains revealed that the numbers of nerve or interstitial cells in the chimeras were very similar to (statistically significantly correlated with) those in their interstitial cell donors. Since chimeras and their interstitial cell donors share the same interstitial cell lineages, this suggests that interstitial cells or their derivatives (nerves and nematocytes) play major roles in determining the nerve and interstitial cell levels in the hydra tissue. It is suggested that some form of homeostatic feedback mechanisms are probably involved in regulating the levels of these cell types.

Download Full-text