Triggering of Wnt3 upregulation upon amputation in hydra. Based on the fact that if a midsection cut and a more apical cut both result in Wnt activation, the triggering of apoptosis in the first scenario and not in the other. Introduction: The decapitated Hydra regenerate their heads through morphallaxis, means, without significant contributions made by cell proliferation or interstitial stem cells. Indeed, Hydra depleted of interstitial stem cells regenerate robustly, and Wnt3 from epithelial cells triggers head regeneration. This process is called morphallactic regeneration (regeneration by cell differentiation).

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Answer 1

Question

Chapter 22, Problem 1DQ

Summary Introduction

To review:

Triggering of Wnt3 upregulation upon amputation in hydra. Based on the fact that if a midsection cut and a more apical cut both result in Wnt activation, the triggering of apoptosis in the first scenario and not in the other.

Introduction:

The decapitated Hydra regenerate their heads through morphallaxis, means, without significant contributions made by cell proliferation or interstitial stem cells. Indeed, Hydra depleted of interstitial stem cells regenerate robustly, and Wnt3 from epithelial cells triggers head regeneration. This process is called morphallactic regeneration (regeneration by cell differentiation).

Expert Solution & Answer

Explanation of Solution

When hydra have cut at its midsection, cells derived from the interstitial stem cells (neurons, nematocytes, secretory cells, and gametes) undergo apoptosis immediately below the cut site. These cells produce Wnt3 before death triggering release of β-catenin in the interstitial cells beneath them, which causes a wave of proliferation in the interstitial cells as well as remodeling in the epithelial cells. Epimorphic regeneration is a process where a variety of cell types differentiates and self-organize or regenerates to rebuild a missing structure. Generally occurs in salamander and hydra or another process known as epimorphosis (regeneration of tissues or organs through dedifferentiation of existing, differentiated adult tissues). Canonical Wnt signaling is significant in normal budding and in head regeneration.

The different mechanism controls regeneration after midgastric bisection in hydra equipped with both epithelial and interstitial cell lineages. The apoptosis process is rapidly induced and Wnt3 secretion among interstitial cells at the head- (but not foot-) regenerating site. Apoptosis is both necessary and sufficient to induce Wnt3 production and head regeneration, even at ectopic sites. The head inhibitor and head activator (Wnts) are both present in the hypostome of hydra, head inhibition gradient falls off rapidly than the head activator gradient. Inhibition of head activator by the head inhibitor induces the formation of budding zone.

Conclusion

Hydra exhibits morphallaxis, and epimorphic regeneration for triggering of Wnt3 upregulation upon amputation in hydra. Certain head inhibition gradients are present in hydra body which prevents any region of hydra body to form head and induce head formation at a specific location.

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Practice Question 8 - Below are two cell signalling pathways that work together to regulate cell growth, proliferation and ultimately the size of organs in O.Extremus. In other closely related organisms, dysfunction of these pathways has been associated with tumor growth. mTOR pathway: 1. Growth factors bind and stimulate the receptors. crosstalk Hippo Pathway 2. Receptors can activate the phosphatidylinositol 3 kinase (PI3K) – Akt signaling pathway. MTOR Pathway 3. The activated Akt, a serine threonine kinase, inhibits the TSC1-TSC2 complex, allowing Rheb to activate mTORC1. Mst PI3K PTEN Lats AKT 4. In parallel, amino acids activate the mTORC1 pathway through a mechanism requiring the Rag- Ragulator complex. (miR-29 YAP TSC2-TSC1 amino acids Rag-Ragulator Hippo pathway: 1. The binding of the ligand activates the receptors which activate Mst and Lats. Rheb cell division MTORC1 organ size 2. YAP activity is modulated by phosphorylation of Mst and Lats. YAP upregulates miR-29, which in…

Practice Question 8 - Below are two cell signalling pathways that work together to regulate cell growth, proliferation and ultimately the size of organs in O.Extremus. In other closely related organisms, dysfunction of these pathways has been associated with tumor growth. MTOR pathway: 1. Growth factors bind and stimulate the receptors. crosstalk Hippo Pathway 2. Receptors can activate the phosphatidylinositol 3 kinase (PI3K) – Akt signaling pathway. MTOR Pathway 3. The activated Akt, a serine threonine kinase, inhibits theTSC1-TSC2 complex, allowing Rheb to activate mTORC1. Mst РІЗК PTEN T Lats АКТ 4. In parallel, amino acids activate the mTORC1 pathway through a mechanism requiring the Rag- Ragulator complex. (miR-29 YAP TSC2-TSC1 amino acids Rag-Ragulator Hippo pathway: 1. The binding of the ligand activates the receptors which activate Mst and Lats. Rheb cell division MTORC1 organ size 2. YAP activity is modulated by phosphorylation of Mst and Lats. YAP upregulates miR-29, which in…

Practice Question 8 - Below are two cell signalling pathways that work together to regulate cell growth, proliferation and ultimately the size of organs in O.Extremus. In other closely related organisms, dysfunction of these pathways has been associated with tumor growth. MTOR pathway: 1. Growth factors bind and stimulate the receptors. crosstalk Hippo Pathway 2. Receptors can activate the phosphatidylinositol 3 kinase (PI3K) – Akt signaling pathway. MTOR Pathway 3. The activated Akt, a serine threonine kinase, inhibits theTSC1-TSC2 complex, allowing Rheb to activate mTORC1. Mst РІЗК PTEN Lats АКТ 4. In parallel, amino acids activate the mTORC1 pathway through a mechanism requiring the Rag- Ragulator complex. miR-29 YAP TSC2-TSC1 amino acids Hippo pathway: 1. The binding of the ligand activates the receptors which activate Mst and Lats. Rheb Rag-Ragulator cell division MTORC1 organ size 2. YAP activity is modulated by phosphorylation of Mst and Lats. YAP upregulates miR-29, which in…

Answer 2

Question

Chapter 22, Problem 1DQ

Summary Introduction

To review:

Triggering of Wnt3 upregulation upon amputation in hydra. Based on the fact that if a midsection cut and a more apical cut both result in Wnt activation, the triggering of apoptosis in the first scenario and not in the other.

Introduction:

The decapitated Hydra regenerate their heads through morphallaxis, means, without significant contributions made by cell proliferation or interstitial stem cells. Indeed, Hydra depleted of interstitial stem cells regenerate robustly, and Wnt3 from epithelial cells triggers head regeneration. This process is called morphallactic regeneration (regeneration by cell differentiation).

Expert Solution & Answer

Explanation of Solution

When hydra have cut at its midsection, cells derived from the interstitial stem cells (neurons, nematocytes, secretory cells, and gametes) undergo apoptosis immediately below the cut site. These cells produce Wnt3 before death triggering release of β-catenin in the interstitial cells beneath them, which causes a wave of proliferation in the interstitial cells as well as remodeling in the epithelial cells. Epimorphic regeneration is a process where a variety of cell types differentiates and self-organize or regenerates to rebuild a missing structure. Generally occurs in salamander and hydra or another process known as epimorphosis (regeneration of tissues or organs through dedifferentiation of existing, differentiated adult tissues). Canonical Wnt signaling is significant in normal budding and in head regeneration.

The different mechanism controls regeneration after midgastric bisection in hydra equipped with both epithelial and interstitial cell lineages. The apoptosis process is rapidly induced and Wnt3 secretion among interstitial cells at the head- (but not foot-) regenerating site. Apoptosis is both necessary and sufficient to induce Wnt3 production and head regeneration, even at ectopic sites. The head inhibitor and head activator (Wnts) are both present in the hypostome of hydra, head inhibition gradient falls off rapidly than the head activator gradient. Inhibition of head activator by the head inhibitor induces the formation of budding zone.

Conclusion

Hydra exhibits morphallaxis, and epimorphic regeneration for triggering of Wnt3 upregulation upon amputation in hydra. Certain head inhibition gradients are present in hydra body which prevents any region of hydra body to form head and induce head formation at a specific location.

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Answer 3

Question

Chapter 22, Problem 1DQ

Summary Introduction

To review:

Triggering of Wnt3 upregulation upon amputation in hydra. Based on the fact that if a midsection cut and a more apical cut both result in Wnt activation, the triggering of apoptosis in the first scenario and not in the other.

Introduction:

The decapitated Hydra regenerate their heads through morphallaxis, means, without significant contributions made by cell proliferation or interstitial stem cells. Indeed, Hydra depleted of interstitial stem cells regenerate robustly, and Wnt3 from epithelial cells triggers head regeneration. This process is called morphallactic regeneration (regeneration by cell differentiation).

Expert Solution & Answer

Explanation of Solution

When hydra have cut at its midsection, cells derived from the interstitial stem cells (neurons, nematocytes, secretory cells, and gametes) undergo apoptosis immediately below the cut site. These cells produce Wnt3 before death triggering release of β-catenin in the interstitial cells beneath them, which causes a wave of proliferation in the interstitial cells as well as remodeling in the epithelial cells. Epimorphic regeneration is a process where a variety of cell types differentiates and self-organize or regenerates to rebuild a missing structure. Generally occurs in salamander and hydra or another process known as epimorphosis (regeneration of tissues or organs through dedifferentiation of existing, differentiated adult tissues). Canonical Wnt signaling is significant in normal budding and in head regeneration.

The different mechanism controls regeneration after midgastric bisection in hydra equipped with both epithelial and interstitial cell lineages. The apoptosis process is rapidly induced and Wnt3 secretion among interstitial cells at the head- (but not foot-) regenerating site. Apoptosis is both necessary and sufficient to induce Wnt3 production and head regeneration, even at ectopic sites. The head inhibitor and head activator (Wnts) are both present in the hypostome of hydra, head inhibition gradient falls off rapidly than the head activator gradient. Inhibition of head activator by the head inhibitor induces the formation of budding zone.

Conclusion

Hydra exhibits morphallaxis, and epimorphic regeneration for triggering of Wnt3 upregulation upon amputation in hydra. Certain head inhibition gradients are present in hydra body which prevents any region of hydra body to form head and induce head formation at a specific location.

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Answer 4

Question

Chapter 22, Problem 1DQ

Summary Introduction

To review:

Triggering of Wnt3 upregulation upon amputation in hydra. Based on the fact that if a midsection cut and a more apical cut both result in Wnt activation, the triggering of apoptosis in the first scenario and not in the other.

Introduction:

The decapitated Hydra regenerate their heads through morphallaxis, means, without significant contributions made by cell proliferation or interstitial stem cells. Indeed, Hydra depleted of interstitial stem cells regenerate robustly, and Wnt3 from epithelial cells triggers head regeneration. This process is called morphallactic regeneration (regeneration by cell differentiation).

Expert Solution & Answer

Explanation of Solution

When hydra have cut at its midsection, cells derived from the interstitial stem cells (neurons, nematocytes, secretory cells, and gametes) undergo apoptosis immediately below the cut site. These cells produce Wnt3 before death triggering release of β-catenin in the interstitial cells beneath them, which causes a wave of proliferation in the interstitial cells as well as remodeling in the epithelial cells. Epimorphic regeneration is a process where a variety of cell types differentiates and self-organize or regenerates to rebuild a missing structure. Generally occurs in salamander and hydra or another process known as epimorphosis (regeneration of tissues or organs through dedifferentiation of existing, differentiated adult tissues). Canonical Wnt signaling is significant in normal budding and in head regeneration.

The different mechanism controls regeneration after midgastric bisection in hydra equipped with both epithelial and interstitial cell lineages. The apoptosis process is rapidly induced and Wnt3 secretion among interstitial cells at the head- (but not foot-) regenerating site. Apoptosis is both necessary and sufficient to induce Wnt3 production and head regeneration, even at ectopic sites. The head inhibitor and head activator (Wnts) are both present in the hypostome of hydra, head inhibition gradient falls off rapidly than the head activator gradient. Inhibition of head activator by the head inhibitor induces the formation of budding zone.

Conclusion

Hydra exhibits morphallaxis, and epimorphic regeneration for triggering of Wnt3 upregulation upon amputation in hydra. Certain head inhibition gradients are present in hydra body which prevents any region of hydra body to form head and induce head formation at a specific location.

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Subscribe now to access step-by-step solutions to millions of textbook problems written by subject matter experts!

Answer 5

Chapter 22, Problem 1DQ

Summary Introduction

To review:

Triggering of Wnt3 upregulation upon amputation in hydra. Based on the fact that if a midsection cut and a more apical cut both result in Wnt activation, the triggering of apoptosis in the first scenario and not in the other.

Introduction:

The decapitated Hydra regenerate their heads through morphallaxis, means, without significant contributions made by cell proliferation or interstitial stem cells. Indeed, Hydra depleted of interstitial stem cells regenerate robustly, and Wnt3 from epithelial cells triggers head regeneration. This process is called morphallactic regeneration (regeneration by cell differentiation).

Expert Solution & Answer

Explanation of Solution

When hydra have cut at its midsection, cells derived from the interstitial stem cells (neurons, nematocytes, secretory cells, and gametes) undergo apoptosis immediately below the cut site. These cells produce Wnt3 before death triggering release of β-catenin in the interstitial cells beneath them, which causes a wave of proliferation in the interstitial cells as well as remodeling in the epithelial cells. Epimorphic regeneration is a process where a variety of cell types differentiates and self-organize or regenerates to rebuild a missing structure. Generally occurs in salamander and hydra or another process known as epimorphosis (regeneration of tissues or organs through dedifferentiation of existing, differentiated adult tissues). Canonical Wnt signaling is significant in normal budding and in head regeneration.

The different mechanism controls regeneration after midgastric bisection in hydra equipped with both epithelial and interstitial cell lineages. The apoptosis process is rapidly induced and Wnt3 secretion among interstitial cells at the head- (but not foot-) regenerating site. Apoptosis is both necessary and sufficient to induce Wnt3 production and head regeneration, even at ectopic sites. The head inhibitor and head activator (Wnts) are both present in the hypostome of hydra, head inhibition gradient falls off rapidly than the head activator gradient. Inhibition of head activator by the head inhibitor induces the formation of budding zone.

Conclusion

Hydra exhibits morphallaxis, and epimorphic regeneration for triggering of Wnt3 upregulation upon amputation in hydra. Certain head inhibition gradients are present in hydra body which prevents any region of hydra body to form head and induce head formation at a specific location.

Answer 6

Chapter 22, Problem 1DQ

Summary Introduction

To review:

Triggering of Wnt3 upregulation upon amputation in hydra. Based on the fact that if a midsection cut and a more apical cut both result in Wnt activation, the triggering of apoptosis in the first scenario and not in the other.

Introduction:

The decapitated Hydra regenerate their heads through morphallaxis, means, without significant contributions made by cell proliferation or interstitial stem cells. Indeed, Hydra depleted of interstitial stem cells regenerate robustly, and Wnt3 from epithelial cells triggers head regeneration. This process is called morphallactic regeneration (regeneration by cell differentiation).

Expert Solution & Answer

Explanation of Solution

When hydra have cut at its midsection, cells derived from the interstitial stem cells (neurons, nematocytes, secretory cells, and gametes) undergo apoptosis immediately below the cut site. These cells produce Wnt3 before death triggering release of β-catenin in the interstitial cells beneath them, which causes a wave of proliferation in the interstitial cells as well as remodeling in the epithelial cells. Epimorphic regeneration is a process where a variety of cell types differentiates and self-organize or regenerates to rebuild a missing structure. Generally occurs in salamander and hydra or another process known as epimorphosis (regeneration of tissues or organs through dedifferentiation of existing, differentiated adult tissues). Canonical Wnt signaling is significant in normal budding and in head regeneration.

The different mechanism controls regeneration after midgastric bisection in hydra equipped with both epithelial and interstitial cell lineages. The apoptosis process is rapidly induced and Wnt3 secretion among interstitial cells at the head- (but not foot-) regenerating site. Apoptosis is both necessary and sufficient to induce Wnt3 production and head regeneration, even at ectopic sites. The head inhibitor and head activator (Wnts) are both present in the hypostome of hydra, head inhibition gradient falls off rapidly than the head activator gradient. Inhibition of head activator by the head inhibitor induces the formation of budding zone.

Conclusion

Hydra exhibits morphallaxis, and epimorphic regeneration for triggering of Wnt3 upregulation upon amputation in hydra. Certain head inhibition gradients are present in hydra body which prevents any region of hydra body to form head and induce head formation at a specific location.

Answer 7

Chapter 22, Problem 1DQ

Summary Introduction

To review:

Triggering of Wnt3 upregulation upon amputation in hydra. Based on the fact that if a midsection cut and a more apical cut both result in Wnt activation, the triggering of apoptosis in the first scenario and not in the other.

Introduction:

The decapitated Hydra regenerate their heads through morphallaxis, means, without significant contributions made by cell proliferation or interstitial stem cells. Indeed, Hydra depleted of interstitial stem cells regenerate robustly, and Wnt3 from epithelial cells triggers head regeneration. This process is called morphallactic regeneration (regeneration by cell differentiation).

Answer 8

Expert Solution & Answer

Explanation of Solution

When hydra have cut at its midsection, cells derived from the interstitial stem cells (neurons, nematocytes, secretory cells, and gametes) undergo apoptosis immediately below the cut site. These cells produce Wnt3 before death triggering release of β-catenin in the interstitial cells beneath them, which causes a wave of proliferation in the interstitial cells as well as remodeling in the epithelial cells. Epimorphic regeneration is a process where a variety of cell types differentiates and self-organize or regenerates to rebuild a missing structure. Generally occurs in salamander and hydra or another process known as epimorphosis (regeneration of tissues or organs through dedifferentiation of existing, differentiated adult tissues). Canonical Wnt signaling is significant in normal budding and in head regeneration.

The different mechanism controls regeneration after midgastric bisection in hydra equipped with both epithelial and interstitial cell lineages. The apoptosis process is rapidly induced and Wnt3 secretion among interstitial cells at the head- (but not foot-) regenerating site. Apoptosis is both necessary and sufficient to induce Wnt3 production and head regeneration, even at ectopic sites. The head inhibitor and head activator (Wnts) are both present in the hypostome of hydra, head inhibition gradient falls off rapidly than the head activator gradient. Inhibition of head activator by the head inhibitor induces the formation of budding zone.

Answer 9

Expert Solution & Answer

Answer 10

Expert Solution & Answer

Answer 11

Conclusion

Hydra exhibits morphallaxis, and epimorphic regeneration for triggering of Wnt3 upregulation upon amputation in hydra. Certain head inhibition gradients are present in hydra body which prevents any region of hydra body to form head and induce head formation at a specific location.

Answer 12

Ch. 22 - Prob. 1DQ Ch. 22 - Prob. 2DQ Ch. 22 - Prob. 3DQ

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