Concept explainers
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).
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.
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.
Want to see more full solutions like this?
Chapter 22 Solutions
Developmental Biology
- 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- ator con miR-29 YAP TSC2-TSC1 lex. 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 turn…arrow_forwardStructures REVIEW QUESTIONS The table below compares structures found in bacterial (prokaryotic) cells with those found in animal and plant (eukaryotic) cells. Indicate by writing Yes or No if the structure is present in the cell types. Cell Wall Cell Membrane Nuclear Envelope Chromosome (DNA) Mitochondria Cytosol Ribosome Lysosome Cytoskeleton Plastids Endoplasmic Reticulum Central Vacuole Peroxisome Golgi Complex LABORATORY 4 Centrosome Cilia Section Bacterial Cell Animal Cell Plant Cellarrow_forwardActivity #1 Explore!!! NEURONS OBJECTIVES: Identify the parts of the neuron. · Give the parts and functions of each part of the neuron. Differentiate the three types of neurons PROCEDURE: 1. Given is a figure of a neuron. Draw it on your paper and then afterwards label its parts. Strecture of a Typical Neuron H 2. Describe and give the function each of the parts. A. B. C. D. E. F. G. H.arrow_forward
- Required information 30s MENINGES Within the skull and vertebral column, the brain and spinal cord are protected by three layers of connective tissue collectively called meninges. From superficial to deep, the meninges consist of the dura mater, arachnoid mater and pia mater. 0:00 1:39 The subarachnoid space lies between the Multiple Choice Arachnoid mater and pia mater Pia mater and surface of the brain and spinal cord Skull and dura mater Dura mater and arachnoid mater 1xarrow_forwardRequired information 30s REFLEX ARC Skin- O Stimulation of a sensory receptor results in the transmission of an afferent impulse along the axon of a sensory neuron. These axons end in the spinal cord. In most cases, the impulse will then travel through an interneuron within the spinal cord to synapse with a motor neuron. 0:00 / 1:09 Interneurons are located in the Multiple Choice Sensory receptor Spinal cord Skin Sensory receptors Effector organ 1xarrow_forwardQuestions (Total word requirement: ~250-350 words) 1. How does a normal cell become a cancerous cell? What has to happen to it? 2. Do mutations that cause cancer in an individual pass down to the person's offspring? Explain and give examples. 3. The video in the Module 3 Mastering Bio: Cancer Discussion Background focuses on the telomerase enzyme role in cancer development. Explain the connection between telomerase activity and cancer. 4. Which component of cell division machinery is frequently targeted by anti-cancer drugs? Can you explain the common side-effects of chemotherapy (e.g. hair loss, mucositis) based on this information?arrow_forward
- Reading Check 6/What is the symptom-free period of a disease called?arrow_forwardSTUDY QUESTIONS The table below presents the criteria to be used in comparing mitosis and meiosis. Provide the missing information. 1. CRITERIA a. chromosome number of daughter cells b. number of cell divisions C. stages d. presence of synapsis e. f. presence of crossing over cell type that undergoes division g. number of daughter cells formed h. i. DNA content of cells at start of division DNA content of daughter cells j. genetic consequences MITOSIS MEIOSISarrow_forwardTASK No 2 A patient, 40 years old, complains of weakness, fatigue, abundant menstruation. Upon examination, the uterine myoma was found. The patient is hospitalized. Questions: 4) What kind of atypical structure is typical for uterine fibroids? Describe it. 5) Describe the atypism of tumor metabolism. 6) What does it mean: the phenomenon of tumor progression? 7) What are the methods of tumors treatment?arrow_forward
- 23-27 TRUE OR FALSE Melanocytes are irregularly shaped and have a single round or ellipsoid nucleus. Langerhans cells are lymphocyte-derived dendritic cells. Distinctive membrane-bound melanosomes, which derive from the Golgi complex. Melanosome maturation occurs in THREE stages. Epidermal Langerhan cells have cell adhesion molecule—A-cadherin.arrow_forwardTASK No 2 A patient, 40 years old, complains of weakness, fatigue, abundant menstruation. Upon examination, the uterine myoma was found. The patient is hospitalized. Questions: 1) What kind of tumors does myoma belong to? 2) What does atypism mean? 3) What are the typical characteristics of tumor that was found in the patient? 4) What kind of atypical structure is typical for uterine fibroids? Describe it. 5) Describe the atypism of tumor metabolism. 6) What does it mean: the phenomenon of tumor progression? 7) What are the methods of tumors treatment?arrow_forward! Required information 1305 MENINGES Within the skull and vertebral column, the brain and spinal cord are protected by three layers of connective tissue collectively called meninges. From superficial to deep, the meninges consist of the dura mater, arachnoid mater and pia mater. O The periosteal layer of dura mater is adherent to the Multiple Choice 0:00 / 1:39 Outer surface of the skull Brain surface Inner surface of the skull Pia mater 1x []arrow_forward
- Human Anatomy & Physiology (11th Edition)BiologyISBN:9780134580999Author:Elaine N. Marieb, Katja N. HoehnPublisher:PEARSONBiology 2eBiologyISBN:9781947172517Author:Matthew Douglas, Jung Choi, Mary Ann ClarkPublisher:OpenStaxAnatomy & PhysiologyBiologyISBN:9781259398629Author:McKinley, Michael P., O'loughlin, Valerie Dean, Bidle, Theresa StouterPublisher:Mcgraw Hill Education,
- Molecular Biology of the Cell (Sixth Edition)BiologyISBN:9780815344322Author:Bruce Alberts, Alexander D. Johnson, Julian Lewis, David Morgan, Martin Raff, Keith Roberts, Peter WalterPublisher:W. W. Norton & CompanyLaboratory Manual For Human Anatomy & PhysiologyBiologyISBN:9781260159363Author:Martin, Terry R., Prentice-craver, CynthiaPublisher:McGraw-Hill Publishing Co.Inquiry Into Life (16th Edition)BiologyISBN:9781260231700Author:Sylvia S. Mader, Michael WindelspechtPublisher:McGraw Hill Education