Genetic analysis of developmental mechanisms in hydra

Development ◽  
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.

scholarly journals Genetic analysis of developmental mechanisms in Hydra. II. Isolation and characterization of an interstitial cell-deficient strain

1978 ◽  
Vol 29 (1) ◽  
pp. 35-52 ◽  
Author(s):  
T. Sugiyama ◽  
T. Fujisawa
Keyword(s):  
Genetic Analysis ◽  
Mutant Strain ◽  
Interstitial Cell ◽  
Interstitial Cells ◽  
Nerve Cells ◽  
Isolation And Characterization ◽  
Developmental Mechanisms ◽  
Hydra Magnipapillata

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.

Genetic analysis of developmental mechanisms in hydra. V. Cell lineage and development of chimera hydra

1978 ◽  
Vol 32 (1) ◽  
pp. 215-232
Author(s):  
T. Sugiyama ◽  
T. Fujisawa
Keyword(s):  
Epithelial Cell ◽  
Epithelial Cells ◽  
Interstitial Cell ◽  
Cell Lineage ◽  
Interstitial Cells ◽  
Nerve Cells ◽  
Polyp Size ◽  
Primary Determinant ◽  
One Year ◽  
Almost All

Chimeric hydra were produced by making use of a strain (nf-1) which lacks interstitial cells, nerve cells and nematocytes. This strain arises by spontaneous loss of interstitial cells from its parental strain (sf-1) (Sugiyama & Fujisawa, 1978). Reintroduction of interstitial cells from other strains into nf-1 leads to the creation of chimeric strains that consisted of epithelial cells derived from strain sf-1 and interstitial cells and their derivatives (nerves and nematocytes) from other strains. In chimeras, interstitial or epithelial cells apparently maintain very stable cell lineages; no indication was obtained that suggested interstitial cell differentiation into epithelial cells or dedifferentiation in the opposite direction during the long courses of chimera cultures (up to one year). Developmental characters of chimeras were examined and compared to those of the epithelial cell (sf-1) and the interstitial cell donors. Almost all of the chimera's characters examined (growth rate, budding rate, tentacle numbers, polyp size, regenerative capacity, etc.) closely resembled those of the epithelial cell donor, but not of the interstitial cell donors. This suggests that epithelial cells, rather than interstitial or nerve cells, are the primary determinant of most, if not all, of hydra developmental characters.

scholarly journals Evaluation of the effects of sdiA, a luxR homologue, on adherence and motility of Escherichia coli O157 : H7

Microbiology ◽  
2010 ◽  
Vol 156 (5) ◽  
pp. 1303-1312 ◽  
Author(s):  
Vijay K. Sharma ◽  
Shawn M. D. Bearson ◽  
Bradley L. Bearson
Keyword(s):  
Escherichia Coli ◽  
Epithelial Cells ◽  
Mutant Strain ◽  
Regulatory Networks ◽  
Double Mutant ◽  
Negative Regulator ◽  
Wild Type ◽  
Reverse Transcription Pcr ◽  
Expression Of Genes ◽  
Genes Encoding

Quorum-sensing (QS) signalling pathways are important regulatory networks for controlling the expression of genes promoting adherence of enterohaemorrhagic Escherichia coli (EHEC) O157 : H7 to epithelial cells. A recent study has shown that EHEC O157 : H7 encodes a luxR homologue, called sdiA, which upon overexpression reduces the expression of genes encoding flagellar and locus of enterocyte effacement (LEE) proteins, thus negatively impacting on the motility and intimate adherence phenotypes, respectively. Here, we show that the deletion of sdiA from EHEC O157 : H7 strain 86-24, and from a hha (a negative regulator of ler) mutant of this strain, enhanced bacterial adherence to HEp-2 epithelial cells of the sdiA mutant strains relative to the strains containing a wild-type copy of sdiA. Quantitative reverse transcription PCR showed that the expression of LEE-encoded genes ler, espA and eae in strains with the sdiA deletions was not significantly different from that of the strains wild-type for sdiA. Similarly, no additional increases in the expression of LEE genes were observed in a sdiA hha double mutant strain relative to that observed in the hha deletion mutant. While the expression of fliC, which encodes flagellin, was enhanced in the sdiA mutant strain, the expression of fliC was reduced by several fold in the hha mutant strain, irrespective of the presence or absence of sdiA, indicating that the genes sdiA and hha exert opposing effects on the expression of fliC. The strains with deletions in sdiA or hha showed enhanced expression of csgA, encoding curlin of the curli fimbriae, with the expression of csgA highest in the sdiA hha double mutant, suggesting an additive effect of these two gene deletions on the expression of csgA. No significant differences were observed in the expression of the genes lpfA and fimA of the operons encoding long polar and type 1 fimbriae in the sdiA mutant strain. These data indicate that SdiA has no significant effect on the expression of LEE genes, but that it appears to act as a strong repressor of genes encoding flagella and curli fimbriae, and the alleviation of the SdiA-mediated repression of these genes in an EHEC O157 : H7 sdiA mutant strain contributes to enhanced bacterial motility and increased adherence to HEp-2 epithelial cells.

scholarly journals The Actinobacillus actinomycetemcomitans Autotransporter Adhesin Aae Exhibits Specificity for Buccal Epithelial Cells from Humans and Old World Primates

2005 ◽  
Vol 73 (4) ◽  
pp. 1947-1953 ◽  
Author(s):  
Daniel H. Fine ◽  
Kabilan Velliyagounder ◽  
David Furgang ◽  
Jeffrey B. Kaplan
Keyword(s):  
Epithelial Cells ◽  
Host Range ◽  
Mutant Strain ◽  
Actinobacillus Actinomycetemcomitans ◽  
Broad Host Range ◽  
Wild Type ◽  
New World Primates ◽  
Old World ◽  
Broad Host Range Plasmid ◽  
Buccal Epithelial Cells

ABSTRACT Cells of the gram-negative periodontopathogen Actinobacillus actinomycetemcomitans express a surface-exposed, outer membrane autotransporter protein, designated Aae, which has been implicated in epithelial cell binding. We constructed a mutant strain of A. actinomycetemcomitans that contained a transposon insertion in the Aae structural gene (aae) and tested the mutant to determine its ability to bind to buccal epithelial cells (BECs) isolated from healthy volunteers. Significantly fewer mutant cells than wild-type cells bound to BECs. A broad-host-range plasmid that contained an intact aae gene driven by a heterologous tac promoter restored the ability of the mutant strain to bind to BECs at wild-type levels. This plasmid also conferred upon Escherichia coli the ability to express the Aae protein on its surface and to bind to human BECs. Aae-expressing E. coli also bound to BECs isolated from six Old World primates but not to BECs isolated from four New World primates or nine other nonprimate mammals, as well as to human gingival epithelial cells but not to human pharyngeal, palatal, tongue, bronchial, or cervical epithelial cells. Our findings indicate that Aae mediates binding of A. actinomycetemcomitans to BECs from humans and Old World primates and that this process may contribute to the host range specificity and tissue tropism exhibited by this bacterium.

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

Development ◽  
1983 ◽  
Vol 78 (1) ◽  
pp. 141-168 ◽  
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).

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

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.

scholarly journals Elimination by Hydra interstitial and nerve cells by means of colchicine

1976 ◽  
Vol 21 (1) ◽  
pp. 1-13 ◽  
Author(s):  
R.D. Campbell
Keyword(s):  
Stem Cell ◽  
Epithelial Cells ◽  
Effective Treatment ◽  
Interstitial Cells ◽  
Nerve Cells ◽  
Digestive Cells ◽  
Hydra Attenuata ◽  
Derivatives Of

Hydra treated with colchicine or Colcemid become depleted of 95–99% of their interstitial cells and derivatives of this stem cell: nematoblasts, nematocytes and nerve cells. A second treatment removes most or all remaining interstitial cells. The most effective treatment is an 8-h immersion of whole Hydra attenuata in 0.04% Colcemid or 0.4% colchicine. Interstitial cells are eliminated through phagocytosis by both ectodermal and endodermal epithelial cells. The endodermal digestive cells send processes through the mesoglea which engulf interstitial cells and retract them into the endoderm. The resultant hydra, though devoid of nematocysts, can be artificially fed: these animals grow and bud and can be used to study the behaviour and development of tissue lacking nerve and interstitial cells.

Genetic analysis of developmental mechanisms in hydra

Development ◽  
1985 ◽  
Vol 90 (1) ◽  
pp. 123-138
Author(s):  
Jun Takano ◽  
Tsutomu Sugiyama
Keyword(s):  
Genetic Analysis ◽  
Mutant Strain ◽  
Brine Shrimp ◽  
Potential Gradient ◽  
Body Axis ◽  
Developmental Mechanisms ◽  
Effect Of Food ◽  
Potential Gradients ◽  
Very High

Effect of food was examined on the budding rate and the developmental gradients of a mutant hydra strain L4. This mutant strain has very high levels of head-inhibition potential gradient along its body axis (Takano & Sugiyama, 1983). It also has a reduced budding capacity when it is cultured using brine shrimp nauplii as food, but its budding capacity is significantly improved when a small amount of tubifex worm tissue is added to its diet of brine shrimp (Takano, 1984). To test whether or not this change of budding rate is correlated with the change in the levels of the head-activation or head-inhibition potential gradients, L4 animals were cultured on the diet of brine shrimp with or without addition of tubifex worm tissue and the budding rates and the gradient levels were examined in these animals. The results showed that food affected the budding rate in L4 without affecting its gradient levels. This suggests that the gradient levels and the budding rate in L4 are uncorrelated to each other, and that therefore the high levels of head-inhibition potential are not the cause for the low budding rate in this strain (cf., Takano & Sugiyama, 1983).

Genetic analysis of developmental mechanisms in Hydra. IV. Characterization of a nematocyst-deficient strain

1978 ◽  
Vol 30 (1) ◽  
pp. 175-185 ◽  
Author(s):  
T. Fujisawa ◽  
T. Sugiyama
Keyword(s):  
Genetic Analysis ◽  
Normal Level ◽  
The Body ◽  
Normal Rate ◽  
Wild Type ◽  
Head Region ◽  
Developmental Defects ◽  
Developmental Mechanisms ◽  
Body Column

The authors have previously found that mutant hydra strains showing various types of developmental defects can be isolated through sexual inbreeding of wild hydra. One such defective strain, called nem-4, contains virtually no stenoteles, one of the four types of nematocysts present in hydra, in its tentacles. However, stenoteles are present at a normal level in the body column of this strain, and they are turned over also at a normal rate. Grafting experiments between the head region of nem-4 hydra and the body column of wild type hydra (and vice versa) showed that wild type stenotele nematocytes can move into nem-4 tentacles but that nem-4 stenotele nematocytes can not move into the wild type tentacles. These observations suggest that the stenotele nematocytes are produced normally by differentiation from the interstitial cells in the body column of nem-4 hydra, but that they are somehow prevented from migrating into the tentacles in this strain.

scholarly journals Role of the Campylobacter jejuni Cj1461 DNA Methyltransferase in Regulating Virulence Characteristics

2008 ◽  
Vol 190 (19) ◽  
pp. 6524-6529 ◽  
Author(s):  
Joo-Sung Kim ◽  
Jiaqi Li ◽  
If H. A. Barnes ◽  
David A. Baltzegar ◽  
Mohanasundari Pajaniappan ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Mutant Strain ◽  
Campylobacter Jejuni ◽  
Dna Methyltransferase ◽  
Wild Type ◽  
Less Invasive ◽  
Human Epithelial Cells ◽  
Methyltransferase Gene

ABSTRACT Mutation of the cj1461 predicted methyltransferase gene reduced the motility of Campylobacter jejuni 81-176. Electron microscopy revealed that the mutant strain had flagella but with aberrant structure. The Δcj1461 mutant was sevenfold more adherent to but 50-fold less invasive of INT-407 human epithelial cells than the wild type.

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