Amber

Amber Yin

__Tobacco Mosaic Virus Investigation__


 * __Relevance:__** The tobacco mosaic virus is a common plant virus among the plant family of Solanaceae. Studies have shown that the reason for this virus comes from people smoking that handle plants. Certain plants have been infected by this method especially tomato. In our experiment, we will infect plants with the TMV virus in order to learn about how it affects different plants, by observing how long it takes until symptoms show, which plants are susceptible, and which plants are most affected.


 * __Goal:__** To learn how the TMV affects different plants, which plants may have immunity to the virus, and how the virus affects the plant’s cells.


 * __Expectations:__** I expect to see certain plants quickly become infected and die, while other plants show no symptoms because of coat-protein-mediated-resistance so they will also live longer.

- How each plant is infected (how much tobacco is used) - How each plant is treated under the same conditions
 * __Variables:__** //Controlled//


 * __Materials:__**


 * tobacco (two pinches from one cigarette) Specify the brand of cigarette that you use for this part of the experiment mortar and pestle
 * 10 ml 0.1 M dibasic potassium phosphate buffer
 * 2 test tubes or small beakers
 * cotton swabs
 * emery board
 * 5 potted plants in potting soil (we used strawberry, mint, and other common house plants.)

1. Prepare the solution for inoculation of your plants as follows: a) Place 2 pinches of tobacco from a cigarette into the mortar. Add 5 ml of buffer and grind the mixture with the pestle until it is a fine slurry. Place the slurry in a test tube or small stoppered or covered vial until it is ready for use. b) Prepare your control solution and place it in an appropriate labeled covered container. 2. Using the emery board, gently abrade (scrape) the surface of some of the leaves of all of your plants. Be careful: DO NOT SCRAPE THE LEAF TOO HARD OR YOU WILL DESTROY THE PLANT. Take a picture of the leaves before and after they have been infected. Marking the leaves to indicate which ones you have infected may also be helpful. 3. Using a cotton swab, apply the tobacco slurry to the abraded leaves of the experimental plants. Set these plants in a designated area, making sure they get enough water and sunlight. 4. Place the plants in a well lit area for a week to 10 days. Observe your plants and record your observations every day. Make notes daily on the condition of all the leaves. Taking pictures is recommended.
 * __Procedure:__**


 * __Appendix 1: Related Terms:__**


 * Buffer** any substance or mixture of compounds that, added to a solution, is capable of neutralizing both acids and bases without appreciably changing the original acidity or alkalinity of the solution.

//Buffer Etymology// 1835, from obsolete verb //buff// "make a dull sound when struck," from O.Fr. //buffe// "a blow;" hence "something that absorbs a blow."

Example: Buffer was needed to neutralize the acids and bases before tobacco could be added.


 * Capsid** The protein shell that surrounds a virus particle

=//Capsid Etymology//= //[From Latin, box.]//

Example: The TMV is made up of two parts, the capsid proteins and the RNA.


 * Chlorophyll** the green coloring matter of leaves and plants, essential to the production of carbohydrates by photosynthesis

//Chlorophyll Etymology// //1819, from Fr.// chlorophyle //(1818), coined by Fr. chemists Pierre-Joseph Pelletier (1788-1842) and Joseph Bienaimé Caventou (1795-1877) from Gk.// khloros //"pale green" (see Chloe) +// phyllon //"a leaf."//

Example: Chlorophyll was destroyed after the plants were infected because the areas with infection were no longer green.


 * Chloroplasts** A plastid in the cells of green plants and green algae that contains chlorophylls and carotenoid pigments and creates glucose through photosynthesis. In plants, chloroplasts are usually disk-shaped and can reorient themselves in the cell to vary their exposure to sunlight. Chloroplasts contain the saclike membranes known as **thylakoids**, which contain the chlorophyll and are arranged in stacklike structures known as **grana.** Besides conducting photosynthesis, plant chloroplasts store starch and are involved in amino acid synthesis. Like mitochondria, chloroplasts have their own DNA that is different from the DNA in the nucleus, and chloroplasts are therefore believed to have evolved from symbiont bacteria, their DNA being a remnant of their past existence as independent organisms.

//Chlorophyll Etymology// //1819, from Fr.// chlorophyle //(1818), coined by Fr. chemists Pierre-Joseph Pelletier (1788-1842) and Joseph Bienaimé Caventou (1795-1877) from Gk.// khloros //"pale green" (see Chloe) +// phyllon //"a leaf."//

Example: We believe that when we infected our plants, we killed the chloroplasts.

Electron Microscope Any of a class of microscopes that use electrons rather than visible light to produce magnified images, especially of objects having dimensions smaller than the wavelengths of visible light, with linear magnification approaching or exceeding a million //Electron Etymology// //coined 1891, from electric;// electronic //is 1902 in the sense of "pertaining to electrons;" 1930 as "pertaining to electronics."// Electronics //(1910) is the branch of physics and technology concerned with the penomenon of electrons in vacuums, gas, semi-conductors, etc.//

=//Microscope Etymology//= //1656, from Mod.L.// microscopium, //lit. "an instrument for viewing what is small," from Gk.// micro- //(q.v.) +// -skopion. //"means of viewing," from// skopein //"look at."// Microscopic //"of minute size" is attested from 1760s.//

Example: The Tobacco Mosaic virus was first seen from an Electron Microscope.

Epidermis a thin layer of cells forming the outer integument of seed plants and ferns  //Epidermis Etymology// //1626, from Gk.// epidermis, //from// epi- //"on" +// derma //"skin."//

Example: The Epidermis was abraded when I scraped the leaf with an emery board.

exchange and water loss
 * Guard Cell** a specialized cell on the undersurface of leaves for controlling gas

//Cell Etymology// //c.// //1131, "small room," from L.// cella //"small room, hut," related to L.// celare //"to hide, conceal," from PIE base// *kel- //"conceal" (cf. Skt.// cala //"hut, house, hall;" Gk.// kalia //"hut, nest,"// kalyptein //"to cover,"// koleon //"sheath,"// kelyphos //"shell, husk;" L.// cella //"store room,"// clam //"secret;" O.Ir.// cuile //"cellar,"// celim //"hide," M.Ir.// cul //"defense, shelter;" Goth.// hulistr //"covering," O.E.// heolstor //"lurking-hole, cave, covering," Goth.// huljan //"cover over,"// hulundi //"hole,"// hilms //"helmet,"// halja //"hell," O.E.// hol //"cave,"// holu //"husk, pod"). Earliest sense is for monastic rooms, then prison rooms (1722). Used in biology 17c., but not in modern sense until 1845. Meaning "small group of people working within a larger organization" is from 1925.// Cellphone //is from 1984.//

Example:

=//Infect Etymology//= c.1374, from L. //infectus,// pp. of //inficere// "to spoil, stain," lit. "to put in," from //in-// "in" + //facere// "perform" (see //factitious//). //Infection// is 1548 in sense of "communication of disease by agency of air or water" (distinguished from //contagion,// which is body-to-body communication). //Infectious// "catching, having the quality of spreading from person to person" is 1542 of diseases, 1611 of emotions, actions, etc. Example:
 * Localized Infection** an infection that is limited to a specific part of the body and has local symptoms.


 * Mesophyll** the internal tissue between the upper and lower epidermal surfaces of a plant leaf

=//Mesophyll Etymology//=

//New Latin mesophyllum, from meso meaning “middle” + Greek phyllon meaning “leaf”//
Example:

//Virus Etymology// //13////92, "venomous substance," from L.// virus //"poison, sap of plants, slimy liquid," probably from PIE base// *weis- //"to melt away, to flow," used of foul or malodorous fluids (cf. Skt.// visam //"poison,"// visah //"poisonous;" Avestan// vish- //"poison;" L.// viscum //"sticky substance, birdlime;" Gk.// ios //"poison,"// ixos //"mistletoe, birdlime; O.C.S.// višnja //"cherry;" O.Ir.// fi //"poison;" Welsh// gwy //"fluid, water,"// gwyar //"blood"). Main modern meaning "agent that causes infectious disease" first recorded 1728. The computer sense is from 1972. Adjective form// viral //was coined 1948.// Example: Tobacco Mosaic Virus is a plant virus.
 * Plant Virus** Any of various viruses that can cause plant disease (e.g., the tobacco mosaic virus). Plant viruses are economically important because many of them infect crop and ornamental plants. Numerous plant viruses are rodlike and can be extracted readily from plant tissue and crystallized. Most lack the fatty membrane found in many animal viruses, and all contain RNA. Plant viruses are transmitted in various ways, most importantly through insect bites, mainly by aphids and plant hoppers. Symptoms of virus infection include colour changes, dwarfing, and tissue distortion. The appearance of streaks of colour in certain tulips is caused by a virus.


 * Protein** Any of a group of complex organic macromolecules that contain carbon, hydrogen, oxygen, nitrogen, and usually sulfur and are composed of one or more chains of amino acids. Proteins are fundamental components of all living cells and include many substances, such as enzymes, hormones, and antibodies, that are necessary for the proper functioning of an organism

//Protein Etymology// //1844, from Fr.// protéine, //coined 1838 by Du. chemist Gerhard Johan Mulder (1802-1880), perhaps on suggestion of Berzelius, from Gk.// proteios //"the first quality," from// protos //"first." Originally a theoretical substance thought to be essential to life, the modern use is from Ger.// Protein, //borrowed in Eng. 1907.// Example:

//Retrovirus Etymology 1977, earlier retravirus (1974), from re(verse) tra(nscriptase) + virus. So called because it contains reverse transcriptase, an enzyme that uses RNA instead of DNA to encode genetic information, which reverses the usual pattern. Remodeled by infl. of retro- "backwards."// Example:
 * Retrovirus** A family of viruses distinguished by three characteristics: (1) genetic information in ribonucleic acid (RNA); (2) virions possess the enzyme reverse transcriptase; and (3) virion morphology consists of two proteinaceous structures, a dense core and an envelope that surrounds the core. Some viruses outside the retrovirus family have some of these characteristics, but none has all three. Numerous retroviruses have been described; they are found in all families of vertebrates.


 * RNA** A polymeric constituent of all living cells and many viruses, consisting of a long, usually single-stranded chain of alternating phosphate and ribose units with the bases adenine, guanine, cytosine, and uracil bonded to the ribose. The structure and base sequence of RNA are determinants of protein synthesis and the transmission of genetic information. Also called //ribonucleic acid//.

//Ribo Etymology// //1931, from// ribo-, //from ribose (q.v.), the sugar component, +// nucleic

=//Nucleic Acid Etymology//= //1892, translation of Ger.// Nukleinsäure //(1889), from// Nuklein //"substance obtained from a cell nucleus."//

Example:

//Virus Etymology// //13////92, "venomous substance," from L.// virus //"poison, sap of plants, slimy liquid," probably from PIE base// *weis- //"to melt away, to flow," used of foul or malodorous fluids (cf. Skt.// visam //"poison,"// visah //"poisonous;" Avestan// vish- //"poison;" L.// viscum //"sticky substance, birdlime;" Gk.// ios //"poison,"// ixos //"mistletoe, birdlime; O.C.S.// višnja //"cherry;" O.Ir.// fi //"poison;" Welsh// gwy //"fluid, water,"// gwyar //"blood"). Main modern meaning "agent that causes infectious disease" first recorded 1728. The computer sense is from 1972. Adjective form// viral //was coined 1948.// Example:
 * RNA Virus** An RNA-containing virus; retrovirus

Solanaceae large and economically important family of herbs or shrubs or trees often strongly scented and sometimes narcotic or poisonous; includes the genera Solanum, Atropa, Brugmansia, Capsicum, Datura, Hyoscyamus, Lycopersicon, Nicotiana, Petunia, Physalis, and Solandra

//No etymology found.//

Example: The Solanaceae plant family is most commonly infected with the Tobacco Mosaic Virus.

//Stoma Etymology//
//“orifice, small opening in an animal body," 1684, from Mod.L., from Gk.// stoma //(gen.// stomatos//) "mouth," from PIE base// *stom-en-//, denoting various body parts and orifices (cf. Avestan// staman- //"mouth" (of a dog), Hittite// shtamar //"mouth," M.Bret.// staffn //"mouth, jawbone," Corn.// stefenic //"palate"). Surgical sense is attested from 1937.//


 * Example:**


 * Systemic infection** is a generic term for infection caused by microorganisms in animals or plants, where the causal agent (the microbe) has spread actively or passively in the host's anatomy and is disseminated throughout several organs in different systems of the host. In the case of animals, throughout organs in the digestive, respiratory, and other systems, especially the circulatory system; in plants, throughout the xylem and/or phloem vessels, and into organs like leaves, stems, roots, tubers, fruits, et cetera.

=//Infect Etymology//= c.1374, from L. //infectus,// pp. of //inficere// "to spoil, stain," lit. "to put in," from //in-// "in" + //facere// "perform" (see //factitious//). //Infection// is 1548 in sense of "communication of disease by agency of air or water" (distinguished from //contagion,// which is body-to-body communication). //Infectious// "catching, having the quality of spreading from person to person" is 1542 of diseases, 1611 of emotions, actions, etc.

Example:


 * Tobacco mosaic virus** (TMV) an RNA virus that infects plants, especially tobacco and other members of the family Solanaceae, showing characteristic patterns (mottling and discoloration) on the leaves

//Tobacco Etymology// 1588, from Sp. //tabaco,// in part from an Arawakan (probably Taino) language of the Caribbean, said to mean "a roll of tobacco leaves" (according to Las Casas, 1552) or "a kind of pipe for smoking tobacco" (according to Oviedo, 1535). Scholars of Caribbean languages lean toward Las Casas' explanation. But Sp. //tabaco// (also It. //tabacco//) was a name of medicinal herbs from c.1410, from Arabic //tabbaq,// attested since 9c. as the name of various herbs. So the word may be a European one transferred to an American plant. Cultivation in France began 1556 with an importation of seed by Andre Thevet; introduced in Spain 1558 by Francisco Fernandes. //Tobacco Road// as a mythical place representative of rural Southern U.S. poverty is from the title of Erskine Caldwell's 1932 novel.

Example: The tobacco from cigarettes are harmful to plants.


 * Virion** A complete viral particle, consisting of RNA or DNA surrounded by a protein shell and constituting the infective form of a virus.

//Virus Etymology// //13////92, "venomous substance," from L.// virus //"poison, sap of plants, slimy liquid," probably from PIE base// *weis- //"to melt away, to flow," used of foul or malodorous fluids (cf. Skt.// visam //"poison,"// visah //"poisonous;" Avestan// vish- //"poison;" L.// viscum //"sticky substance, birdlime;" Gk.// ios //"poison,"// ixos //"mistletoe, birdlime; O.C.S.// višnja //"cherry;" O.Ir.// fi //"poison;" Welsh// gwy //"fluid, water,"// gwyar //"blood"). Main modern meaning "agent that causes infectious disease" first recorded 1728. The computer sense is from 1972. Adjective form// viral //was coined 1948.//

Example: A TMV viron consists of the capsid and the RNA.


 * Virus** an ultramicroscopic (20 to 300 nm in diameter), metabolically inert, infectious agent that replicates only within the cells of living hosts, mainly bacteria, plants, and animals: composed of an RNA or DNA core, a protein coat, and, in more complex types, a surrounding envelope.

//Virus Etymology// //13////92, "venomous substance," from L.// virus //"poison, sap of plants, slimy liquid," probably from PIE base// *weis- //"to melt away, to flow," used of foul or malodorous fluids (cf. Skt.// visam //"poison,"// visah //"poisonous;" Avestan// vish- //"poison;" L.// viscum //"sticky substance, birdlime;" Gk.// ios //"poison,"// ixos //"mistletoe, birdlime; O.C.S.// višnja //"cherry;" O.Ir.// fi //"poison;" Welsh// gwy //"fluid, water,"// gwyar //"blood"). Main modern meaning "agent that causes infectious disease" first recorded 1728. The computer sense is from 1972. Adjective form// viral //was coined 1948.//

Example: TMV is a virus because it contains RNA as its genetic information.

__Appendix 2:Big Ideas:__

1. Differences Between Bacteria and Viruses. There is a big difference between viruses and bacteria. Probably the biggest difference is that viruses must have a living host such as a plant or animal, while bacteria is able to live off of non-living hosts. Viruses are also the smallest and simplest form of life. They are actually about 10 to 100 times smaller than bacteria. Another difference between viruses and bacteria are that viruses attack their host cells in order to inject their own genetic information into the cell, but bacteria do not. Bacteria are able to reproduce by themselves. Viruses only carry the information that is needed for reproduction (DNA, RNA). The actual reproduction takes place in the host.

Basic structure of a bacterium TMV (tobacco mosaic virus) This idea is relevant to our experiment because we are infecting plants with the tobacco mosaic virus, which is a virus that infects plants. Because we are using a virus, it may be more difficult for the plant to destroy the disease, or even to stop the disease from spreading to other parts of the plant. If we were to infect it with a bacterium instead, it would most likely be easier for the plant to fight the disease, and our experiment would last for a shorter period of time.

2. Coat-Protein-Mediated Resistance

This is a phenomenon found in plants that states that some plants have developed immunity to certain viruses such as the TMV.

This diagram shows the procedure to create a transgenic plant. Certain transgenic plants accumulate a coat of the tobacco mosaic virus, and are protected from the TMV because of this phenomenon (coat-protein-mediated resistance)

This idea is relevant to our experiment because when we observed the infected plants, w were able to notice that certain plants showed symptoms, while other plants did not. This shows that some plants could have developed immunity to the tobacco mosaic virus. In humans, in order to stop a virus, you must first prevent it from infecting you. Vaccines are made to prevent a certain virus from infecting you. The coat-protein-mediated resistance is like a vaccine for a plant, immunity.

3. RNA viruses

RNA viruses are viruses that use RNA as their genetic material and do not use DNA in order to multiply. The RNA is usually single-stranded occasionally it will be double stranded. RNA viruses generally have very high mutation rates because they lack DNA polymerases. DNA polymerases are able to find and fix mistakes. Without them, damaged RNA cannot be repaired.

This is a diagram that shows other RNA viruses like the Tobacco Mosaic Virus. The TMV is a RNA virus which means it is a virus that only has one strand of ribonucleic acid, instead of DNA.

In our experiment, we used the tobacco mosaic virus, which is an RNA virus. We infected our plants with this specific RNA virus. RNA viruses multiply faster than DNA viruses, so our plants were infected quicker than other viruses. But since it infects faster, it also means that the virus is more likely to make a mistake when it multiplites because it does not contain DNA polymerases. A lack of this may also cause the virus to be weaker.

Differences Between Bacteria and Viruses. http://www.cfsan.fda.gov/~dms/qa-fdb38.html

Coat-Protein-Mediated Resistance http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1692544

RNA viruses http://www.answers.com/library/Wikipedia-cid-363066056