Wolbachia is a common microbial symbiont that infects insects, including certain species of Drosophila. Bacteria within this genus are capable of propagating their transmission through Drosophila populations by manipulating an infected host’s ability to reproduce (Hamilton & Perlman, 2013). Wolbachia are able to create a selective pressure favoring their transmission by preventing infected fruit flies from having offspring with uninfected flies. Although these microorganisms disrupt host reproduction capabilities, they also confer fitness benefits. These bacteria provide Drosophila with increased resistance against multiple RNA-viral infections. The specific mechanisms of how they provide defense are currently speculative. This discovery has sparked questions regarding whether previously assumed parasites may in fact be mutualistic organisms (Hamilton & Perlman, 2013). One of the main problems with studying this symbiotic relationship in the lab is that Wolbachia cannot be cultured (Teixeira et al., 2008). Therefore, it is possible that ability to confer viral protection may be associated with other intracellular bacteria. However, studies have been able to conclude that the presence of Wolbachia in infected flies is almost exclusively associated with viral resistance (Teixeira et al., 2008). Future research groups hope to study into this symbiotic relationship in an attempt to pursue new methods of control over vector-borne diseases (Chrostek et al., 2013).
1. Chrostek E, Marialva M, Esteves SS, Weinert LA, Martinez J, Jiggins FM, & Teixeira L (2013) Wolbachia variants induce differential protection to viruses in Drosophila melanogaster: A phenotypic and phylogenomic analysis. PLoS Genetics 9(12).
2. Hamilton PT ...
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...ionship between these two organisms, as evidenced by the algae’s intracellular invasion into the embryo’s tissue. The specific details regarding this anatomical relationship are still unclear, mostly as a result of past failures to culture algae from the oviducts of pregnant salamanders (Kerney et al., 2011). Furthermore, it remains unknown how Oophila are able to locate spotted salamander eggs (Graham et al., 2012).
1. Graham E, Fay S, Davey A, & Sanders R (2012) Intracapsular algae provide fixed carbon to developing embryos of the salamander Ambystoma maculatum. The Journal of Experimental Biology 216(3): 452-459.
2. Kerney R, Eunsoo K, Hangarter R, Heiss A, Bishop C, & Hall B (2011) Intracellular invasion of green algae in a salamander host. Proceedings of the National Academy of Sciences of the United States of America 108(16): 6497-6502.
Kuballa A. & Elizur, A. 2007. Novel molecular approach to study moulting in crustaceans. Fisheries Research Agency Bulletin, Vol. 20, pp. 53-57
Hyla versicolor, commonly know as the Gray Tree Frog or the Eastern Gray Tree Frog, is an amphibian that is referred to as the “Chameleon of the Frog world” (Craighead, 2004, p.1) because of its ability to change colors. “This frog was once thought to be the same species as the Cope’s Gray Tree Frog”. They can only be distinguished by their calls and the fact that the Cope Gray Tree Frog is diploid while the Gray Tree Frog is tetraploid (NPWRC, 2004). The Gray Tree Frog is classified as follows:
Bloodborne pathogens are viruses that deteriorate cells within the body. A virus is a submicroscopic parasitic organism that feeds on cells. Viruses are dependent on cells for their nutrients so the virus survive and reproduce. Every virus consists of either deoxyribonucleic acid (DNA) or ribonucleic acid (RNA). A virus can contain a strand of one or the other, but not both. This RNA or DNA is contained within a protein shell for protection. A virus is a parasite that is dependent upon cells for metabolic and reproductive requirements. By using the cell the virus makes the host very ill by redirecting cellular activity to make more viruses.
Disease and parasitism play a pervasive role in all life. Many of these diseases start with microparasites, which are characterized by their ability to reproduce directly within an individual host. They are also characterized by their small size, short duration of infection, and the production of an immune response in infected and recovered individuals. Microparasites which damage hosts in the course of their association are recognized as pathogens. The level of the interaction and the extent of the resultant damage depends on both the virulence of the pathogen, as well as the host defenses. If the pathogen can overcome the host defenses, the host will be damaged and may not survive. If on the other hand the host defenses overcome the pathogen, the microparasite may fail to establish itself within the host and die.
In absence of calcium carbonate, coral and shellfish can’t survive. The ecosystem of ocean depends on these organisms because they offer a large source of food at the bottom of the food chain. They need to be abundant in order t...
Fox, R. 2001. Invertebrate Anatomy OnLine: Artemia Franciscana. Lander University. http://webs.lander.edu/rsfox/invertebrates/artemia.html, retrieved February 13, 2011.
The outer layer of a reef consists of living animals, or polyps, of coral. Single-celled algae called zooxanthellae live within the coral polyps, and a skeleton containing filamentous green algae surrounds them. The photosynthetic zooxanthellae and green algae transfer food energy directly to the coral polyps, while acquiring scarce nutrients from the coral. The numerous micro habitats of coral reefs and the high biological productivity support a great diversity of other life.
Drosophila melanogaster, commonly known as fruit fly, is mainly used as a human disease model organism for genetic analysis. It was during the 20th century that D. melanogaster was considered as the most significant model organism. D. melanogaster is small in size, and it has a short life span with a good reproduction rate, perfect for raising in large number and generation counts for genetics experiments. Additionally, it has a small genome which makes it easier for geneticists to keep track of changes in molecular level. Geneticists were able to uncover many human genetic diseases through the homologous genome of human and fruit flies. It started out with a small group of people led by Thomas Hunt Morgan at Columbia University. Many principles and rules of transmission genetics that are still being used in the generation of today were established in the laboratory of Dr. Morgan. Many animal models were being used before fruit flies. Using the whole-animal as a model set limitations to the types and amounts of experiments can be conducted. The use of Drosophila was able to led geneticists to overcome these limitations with tremendous promises in finding greater quality results. It was Frank Lutz, who wrote many papers on Drosophila, which introduced Drosophila to Dr. Morgan. Many experimental works on plants and animals were carried out on Drosophila instead. Through Drosophila, the discovery of mutation, recombination, relocation of chromosome, and many others were made possible. The cinnabar, cn, gene encodes an enzyme essential in the eye color formation of drosophila. It codes for the enzyme, kynurenine-3-monooxygenase, that is essential in the biological pathway of ommochrome for the brown pi...
The Axolotl, a crucially endangered neotenous species of mole salamander, has adapted to fit its environment so it can easily catch food and evade predators. The Axolotl’s habitat is the lake system of Xochimilco that is near Mexico City, Mexico. This shallow, fresh water lake complex has a temperature range of 6- 20°C and a pH of 7- 12. The complex also has the Axolotl’s primary food sources of mollusk, insect larvae, and other crustaceans. However, with the introduction of foreign species such as the Asian Carp and the African Tilapia, the Axolotl now has predators that may eat and threaten it, and it has competition for the animals it usually eats. Fortunately, the Axolotl has developed adaptations that aid it in catching food and evading predators. To help it catch food the Axolotl’s teeth are shaped like cones, so that its “vacuum” action of sucking in as much water in order to also eat food is aided by the shape of the teeth, which allow it to grip, rather than chew. To aid them in avoiding predators they are able to metamorphose so that they use their lungs more than their gill, which allows them to leave very toxic waters and the predators within. Another adaption that helps them deflect any predator is that they are able to regenerate body parts that have been lost, allowing them to stay as strong as possible. Axolotl’s have adaptations that aid their survival from predators in the lake complex Xochimilco that they reside in.
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.
middle of paper ... ... World Book Inc, 2000. Davis, Lloyd S. and John T Darby. Penguin Biology. San Diego: Academic Press, Inc., 1990.
Porifera is the most simplistic phylum under the kingdom Animalia. The sponges have no tissue layers, but instead an interior and exterior layer with a gelatinous middle layer that separates the two. They are the only phylum with asymmetrical symmetry. Throughout the advancing phyla it will be shown this trait is lost. Porifera lacks a proper digestive system, but a canal system allows the sponges to filter feed. Along the inside of a sponge, flagella pump water through the sponge’s body. This process brings in oxygen and other small organisms and then flows out the top of the sponge, the osculum, removing waste by diffusion. Sponges lack a circulatory system, as does many of the first couple of phyla. A coinciding factor could be their small size. A nervous system is also missing, but very basic nerve cells within the pores sense the water currents. Gas exchange occurs through these pores. Reproduction in sponges can be asexual by budding, gammation, or fragmentation. Some sponges can also have sexual reproduction occur as an egg gets released and fertilized in the open water by free floating sperm. After this stage they cling onto rock and begin their sessile, basic, life....
O'Brien, Stephen J., and Michael Dean. "In Search of AIDS-Resistance Genes." Scientific American. September 1997: 44-51.
Campbell, N. A. & J. B. Reece, 8th eds. (2008). Biology. San Francisco: Pearson Benjamin Cummings.