Regeneration is a process in which tissue molds itself into an exact replica of an injured or severed part. The process of regeneration depends on different factors such as the environment and the development of the organism in question (Br, 1955). Regeneration occurs in several steps and the organism must have the ability to perform each one for successful regeneration with minimal loss of necessary function. First, after a wound is made muscular contraction closes up the wound (Pellettieri et al., 2010). Next a blastema, a group of undifferentiated cells, forms and will differentiate into the missing parts. Lastly the undifferentiated cells go through epimorphosis where the lost parts are formed by the blastema (Reddien & Sánchez Alvarado, 2004).
One organism well suited for regeneration is Dugesia dorotocephala, more commonly known as black planaria. Planarians are flatworms classified under the phylum Platyhelminthes and are bilaterally symmetrical. They are usually found in freshwater streams and ponds (Br, 1955). Planarians are unique in which they can reproduce both asexually and sexually. Planarians can reproduce asexually through transverse fission. Planarians are also hermaphrodites in which they can reproduce through cross fertilization. Planarians prefer to reproduce through fission where the organism splits in two and regenerates itself (Curtis & Schulze, 1933).
Past experiments using Dugesia dorotocephala, show the ability of planaria to regenerate after severing the organism into different parts (Sánchez Alvarado, 2006). Planaria with transversal cuts below the head and above the tail will produce regenerated segments due to the planaria’s ability to form Neoblasts and undergo epimorphosis to create new body se...
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... many organs that would prove vital for scientists to explore regeneration in stem cells in humans (Rink, 2013). The importance of regeneration in planaria is giving scientists insight into how stem cells can be used for human purposes. The regeneration of advanced organs could not only impact planarian livelihood but may revolutionize modern medicine.
Through the continuing studies focused on regeneration and stem cells, scientists can try to see how manipulate totipotent cells found in humans to regenerate into any cell needed throughout the body (Wagner et al., 2012). Humans will benefit from advances in regeneration when faced with degenerative diseases that affect the muscular system or major organs necessary for life. Regeneration can help rebuild organs or muscles damaged by infection or disease and change medicine and human health (Salvetti et al., 2009).
The cells unique nature has scientists intrigued to do research with the focus of finding a way that these cells can be used to replace patients’ injured or diseased tissues. Advancement is made to all the three types of stem cells namely embryonic stem cells, adult stem cells in addition to induced pluripotent cells. Embryonic cells are the building blocks of an embryo that is developing, and can develop into almost all body cell types. Somatic cells are found in the body tissues. They renew and regenerate in healthy bodies. The third type which is induced pluripotent is genetically modified embryo cells from skin cells.2 Research on these cells are geared towards saving humanity; a noble course.
The focus of this lab on planaria regeneration and development. Having been taught the gradient of morphogen and there were many experiments testing this possible phenomenon of regrowth. In a planarian there is a single adult stem cell type called the neoblast. Neoblast are abundantly present throughout the body and it divides continuously. This neoblast has the ability to regenerate different cell and organ types in the planarian, from the brain, digestive system, the sensory system to even the reproductive system. With this continuous stream of continuous division of cells it allows the cells of the planarian to be rapid in self-renewal of the entire
New cells are often produced in the body during growth and development. In addition, new cells also develop as the body repairs and remodels its tissues after an injury. These new cells come from mesenchymal stem cells (MSCs), which are considered as multipotent cells. MSCs are found in various parts of the body during growth and development, but in adults, they are present in the bone marrow, where they later differentiate, mature and migrate to become more specialized cells with unique functions. These cells' potential to develop into bone cells, cartilage cells, muscle cells and fat cells makes their role in regeneration, repair and remodelling important, especially when the body undergoes the normal process of aging or recovers from disease or injury.
The objective of this experiment was to test the effect of light exposure on the regeneration of Dugesia dorotocephala. Dorotocephala is a species which belongs to the kingdom Animalia, class Turbellaria, order Seriata, these worms are classified in the suborder Tricladida based on the three main branches of their digestive system. They are further subdivided based upon ecological habitat. They come in freshwater, marine and terrestrial forms (Alvarado, Reddien). they belong to the family Planariidae and genus Dugesia. These creatures display bilateral symmetry and are classified as metazoans (eumetazoans). Dugesia are found in freshwater habitats in various regions of the world. They inhabit places in Africa, the Middle East, Europe, Asia and even parts of Australia. These small animals tend to be elongated with a triangular head. They possess a dorsal surface coated in shades of grey, black and brown, and a ventral which is a paler shade than the dorsal side. In general they are small and soft bodied which allows them to hide in tight spaces. They are classified as free living and lack a coelom, a hemal system and a circulatory system. Because of this many of their functions depend on diffusion. Freshwater turbellarians are benthic inhabitants of lakes, ponds, springs and streams. Their bodies are covered with cilia and they possess a syncytial epidermis. These small animals lack appendages and rely on cilia to glide over surfaces.
Flatworms belong to the phylum Platyhelminthes. They have the simplest body plan of all bilaterally symmetrical animals. They are called flatworms because their bodies are compressed. The mouth is the only opening into the digestive cavity the flatworms have. Food is taken in through this hole and wastes are discharged also through this hole. Flatworms have a well-defined nervous, muscular, excretory, and reproductive system. The flatworm distributes the food it digests through a digestive tube that branches throughout all of its body parts. The fact that the worm’s body is flat serves many purposes. It allows the worm to hid in small spaces, to fit into the opening of other animals if the worm is parasitic, and it means that all the cells are close enough to the surface for exchange of oxygen and carbon dioxide with the environment (Meinkoth 399).
Descriptions and articles about the Tongue Worms (Pentastomida) - Encyclopedia of Life. (n.d.). Retrieved November 13, 2015, from http://eol.org/pages/2630868/details
In the 1900’s, T.H. Morgan began to study planarian regeneration. In order to study the regeneration of old tissue into new tissue, Morgan began to study with “cell marking experiments” (Alvarado and Newmark, 4). The cell marking experiments were carried out “by cauterizing pigment stripes and
Jellyfish have reproductive cycles that involve a sessile polyp and a free-living medusa state. The polyp is asexual, while the medusa is sexual (Williamson et al. 121). P. physalis actually consist of colonies of many small organisms. A single Man-of-War contains both polyp and medusal stage organisms, with several different types of polyps and medusae in a colony (Halstead, Poisonous 94-95)
The battle between sexual and asexual reproduction is a competition that has been ongoing for millions of years. Somewhere along the way due to its higher level of genetic variation, sexual reproduction was able to overcome the two fold advantage of asexual reproduction, and now dominates reproduction in organisms. However, some types of organisms such as worms and corals have acquired the ability to reproduce both sexually and asexually. The purpose of this paper is to explore the differences in asexual and sexual reproduction both from a biological and an evolutionary standpoint and to explain why evolution has made it possible for soft corals to reproduce both sexually and asexually.
The process of reviving an extinct species is not overly complicated, but it does require a few elements that may be hard to obtain from a species. In order to actually to be eligible for revival a species must have only gone extinct in the last 800,000 years (ngm.nationalgeographic.com). If a species went extinct before that, the environment that it lived in is gone and throwing the organism into this time period’s environment could have disastrous consequences. Enough DNA to sequence the organism must also be present, this assures that we know exactly what makes up the organism and allows us to have the complete “instructions” for the organism before the process starts. Also, an organism must have a close e...
Paragonimus westermani (P. westermani) is part of the phylum Platyhelminthes. Platyhelminthes are flatworms, and are characterized by being acoelomate, triploblastic, and having a simple bilateral symmetry (Berkley.edu). The P. westermani is a member of the Trematoda class. Trematodas are flukes (parasite flatworms) that live inside vertebrates as their primary hosts and inside mollusks as intermediate hosts (wikipedia.org-trematoda). The parasite’s order is Plagiochiformes and suborder is Plagiochiata. The family of the P. westermani is Troglotrematidae. Organisms in this family are oval-shaped, thick flukes whose teguments are covered in spines. Paragonimus, its genus, usually describes parasites of carnivorous mammals; however, this is not always accurate. Although there are 48 species in the Paragonimus genus, westermani is the most prevalent worldwide (Roberts 277).
All human life starts with an ovum and a sperm. Cells then ascend in the fertilized ovum, which after a few days in the womb grow into embryonic stem cells. These cells are much unspecialized and have the ability to develop into all of the 220 human cell categories. An entire human being cannot develop from these cells as they are. They need to continue their development in the womb until they change into mature, distinguished cells which then take over a specific function of the body. Throughout our lives however, we have cells that remain much unspecialized. The regeneration of our skin, for instance, is a continuing process and continues until we expire. Wounds heal. Hair grows. We live with cells which are very unspecialized, can remain to divide as we go through life and help our body to renew and repair itself. These are the cells used in stem cell therapy in India. Adult cells have been and continue to be found in just about every body tissue; the hair, the brain, the liver, the blood, the bone marrow, etc. If body tissue is impaired, these stem cells flock to the smashed region to repair it. This offers the body with its own repair system, and modern therapy is destined to exploit this
After Bonnet’s aphids gave birth to ninety-five offspring through parthenogenesis, Bonnet wrote to Réaumur of his success. Réaumur then read Bonnet’s letter to the French Academy of Sciences leading to Bonnet being officially named a correspondent in the experiment (Lawrence). Bonnet’s experiments were then repeated and refined by multiple biologists throughout the rest of the eighteenth century. However, progress came slowly. The first significant discovery of parthenogenesis in vertebrates did not occur until the 1950’s when scientists observed the process in certain strains of turkeys. Later, in the 1990’s, scientists observed parthenogenic tendencies in crustaceans such as brine shrimp. Unfortunately, neither of these species were able to reproduce by parthenogenesis in labs (Booth). After this monumental observation, biologists began to investigate the natural process of parthenogenesis in vertebrates living in the wild. The scientists specifically searched for a species that primarily reproduced by parthenogenesis, in an attempt to successfully replicate the process in labs. Through this research, it is now known that snakes,
genetic code. When earthworms are cut in half, they regenerate the missing parts of their
Since the beginning of civilization, doctors have been searching for ways to repair, recreate, or otherwise replace damaged parts of the body. Procedures which seem complex even by today’s standards, such as a skin graft for facial reconstruction, have been performed since as long as 1000 years ago. The concept of regeneration has even been acknowledged as far back as the 8th century BC in the Greek myth of Prometheus, in which Prometheus was punished by having an eagle, Ethos, eat his liver each day, only to have it regenerate by nighttime and be pecked out again the next day....