Writing in Biology

Mechanical damage by cutting leaves has shown less response in plant defenses than herbivore damage because enzymes released by herbivores trigger a greater response. Mechanical damage increases concentration of jasmonic acid less than herbivore damage (McCloud and Baldwin 1997). The amount of trichomes increases slightly with clipping leaves, but not like damage from herbivores (Björkman et al. 2008). Applying jasmonic acid has been shown to increase trichrome growth without damage from herbivores. Trichomes are hair-like defensive structures that grow on the leaves of plants that impede movement. Jasmonic acid induces creation of secondary defensive compounds that are less favorable to herbivores and impede herbivore growth (Tian et al. 2012). Mechanical damage with treatment of jasmonic acid may produce the best results for herbivore deterrence.

The reaction of plants to stress from their environment involves a series of pathways which induce defenses (Tian et al. 2014). These pathways involve several hormones which trigger the defense responses in plants. Jasmonates are stress-induced phytohormones that incorporate biotic and abiotic cues that regulate plant growth, development, and defense responses. Jasmonic acid is a hormone plants release to control the responses from herbivore consumption. While impeding growth, the application of jasmonic acid to plants has been shown to enhance the treated plant’s natural defenses (Huang et al. 2017).

On February 21, 140 surviving plants were transplanted to one-gallon pots using Pro Mix BX general purpose soil with mycorrhizae (Premier Horticultural Inc., Quakertown, PA) and treatment fertilizer was added (Osmocote Classic 14-14-14, Scotts-Sierra Horticultural Products Company, Marysville, OH). Treatment and fertilizer amount was randomized, 70 plants were assigned treatment and 70 were not. Half the plants in each treatment group received one teaspoon of fertilizer, the other half received two. After application of fertilizer, plants were put onto greenhouse bench and watered. Plants were watered daily. 

Plant height was then recorded on surviving plants on March 7. Dead plants were discarded. Treatment of mechanical damage was done by cutting off half the new leaflets and one spray of 0.5mM solution of jasmonic acid in acetone was applied. Control received one spray of acetone and no mechanical damage. Plants were placed on a bench in the greenhouse for 14 days so treatment could take effect. 

On March 21, herbivore preference was tested. One new leaf from the treatment group and one from the control, both having received the same amount of fertilizer, were put into a 15 cm petri dish with one tobacco hornworm Manduca sextaordered from Great Lakes Hornworm. There were 84 replicates of herbivore preference experiment. A photo of the leaves pre-hornworm was taken, then again after 18 hours of hornworm exposure. LeafByte was used to determine percentage of each leaf consumed. On March 28, height, root and shoot biomass were measured, and flowers per plant were counted. 

Experiment began January 19, 2019. Tomato species Lycopersicon lycopersicum, a dwarf variety that matures in 50 days, was used. Seeds used were “Tumbler Hybrid Tomato” (Lake Valley Seed, Boulder, CO). Seeds were sown into two 128-plug flats with a moist seed starter soil (Organic Starter Premium Potting Mix, Epsoma, Millville, NJ). Flats were placed on a greenhouse bench with natural light. Germination was induced by placing onto a heat mat. On February 5, 100 ppm of 20-10-20 fertilizer was added at every watering. Fertilizer was increased to 200 ppm after 7 days of growth.

          In this experiment, trimyristin was isolated via extraction from nutmeg using tert-butyl methyl ether. The product was recrystallized using acetone, and hydrolysis was performed to obtain myristic acid. The percent yield of crude trimyristin from nutmeg was 49.20 %. The melting point of the crude was 51 - 55 °C. The percent recovery for the first recrystallization of trimyristin was 39.68 %, and the melting point for this sample was 53 - 56 °C. The percent recovery for the second recrystallization of trimyristin was 65.64 %, and the melting point for this sample was 54 - 56 °C. The relatively low percent recoveries from the recrystallizations could have been due to the use of excess acetone. The known melting point for trimyristin is 56 - 57 °C, which is similar to, but slightly higher than, the experimental melting points, possibly due to the presence of impurities. The range of melting points became narrower from the crude sample, to the first recrystallized sample, to the second recrystallized sample, most likely due to the decreasing amount of impurities following each recrystallization process. The percent yield of myristic acid from trimyristin was 65.14 %, and the melting point was 51 - 52 °C. The known melting point of myristic acid is 54.4 °C, which is similar to, but slightly higher than, the experimental melting point, possibly due to remaining impurities in the sample.

With this new retrovirus killing domestic dogs, I believe that in order to save the species, the breed that should receive the vaccine should be the basenji. The basenji is an African domestic dog breed. It is considered to be a basal breed, meaning it is genetically very similar to wild dogs like dingos and wolves. Its lineage is thought to have begun in Ancient Egypt, based on illustrations and dog mummies in tombs. Being a basal breed, it has not been modified to the extremes like many modern breeds today. Modifications ranging from the smushed face of the pug (which makes it hard for them to breath) to the dachshund whose legs are so short that sometimes they cannot support their own bodies. Those extreme modification also often include inbreeding or puppy mills which harms all the dogs involved. 

If the basenji were to be saved, dog breeding could essentially and eventually be re-done with better methods to insure that future breeds could face little to no health disorders. According to the cladogram on the Science Magazine website, the basenji eventually gave rise to the husky, malamute, shiba inu, chow chow, and more which then gave rise to others. The basenji, once numerous, could act as a template for new breeds. Overtime, based on environment (climate, human interaction, etc.) new breeds could begin to develop. 

    To help combat the sharply declining cheetah populations, countries in Africa have placed them under protection under the law in areas where they still exist and some areas of its historic range. These laws do still allow for farmers to kill cheetahs in order to protect their farm animals (Durant). The government sometimes offer incentives to farmers to promote coexistence with the animal. These countries also have monitored, protected land and parks, as well as educate the community. In Iran, the Asian Cheetah is protected within 5 national parks and wildlife refuges, and in 2009 the Afghan government made all hunting and trading illegal even though it may be extinct in the country.

 The decline is cheetahs throughout their range is mostly due to capture and trade, as well as being hunted for their skins. Historically, they were hunting trophies for Europeans who traveled to Africa in the 1800s. While it is illegal to hunt them today, they are still poached for their skins or captured to be used as exotic pets. Another large contributor to their threatened status is that they face large habitat loss. Urbanization, and agriculture disturb their natural areas reducing their range, so much so that there are now areas of protected land for them, hoping to save the remaining numbers. But they are those that live outside those lands and face conflict with farmers who kill the cheetahs to protect their livestock. Human expansion has also effected the cheetahs food source. In some areas, it is hard for cheetahs to find food, and instead they will try to prey on farmed animals and risk death. A biological contributor to decline is that since the numbers of cheetah are already so low, the chances of inbreeding is higher, making members of a population very close genetically. If a disease were to befall a couple individuals, it could potentially wipeout the entire population in that area. 

    The cheetah (Acinonyx jubatus) is a wild cat found scattered around in small parts of Africa and in Iran. It is famous for being the fastest land animal on the planet, reaching speeds up to 75 miles per hour. There are five subspecies; four that are African and one that is Asian. According to a research paper titled The global decline of cheetah and what it means for conservation by Sarah M. Durant and her team, the cheetah’s historic range was most of Africa (excluding parts of central Africa, Egypt, and Madagascar) and the Middle East into India. Today, cheetahs have lost 98% of their range in Asia, and the Asian Cheetah (Acinonyx jubatus venaticus) is critically endangered with an estimated 50 individuals. In Africa, the remaining four subspecies live only on 13% of the land they once inhabited, causing the Northwest African Cheetah subspecies (Acinonyx jubatus hecki) to also become critically endangered. As of 2014, the known cheetah population is about 6700 individuals over 29 subpopulations (Durant).