Saturday, March 9, 2013

Prompt 1, Big Idea 3

On pages 86-87, Dr. Moalem discusses the defense mechanism celery uses in order to protect itself from predators. Celery produces psoralen (a toxin that can damage DNA and cause sensitivity to sunlight in humans). Humans don't usually fall ill after they eat celery, but humans who deal with celery a lot constantly have skin problems, like farmers. Regular farmers use synthetic pesticides on celery to ward off insects. Organic farmers do not use synthetic pesticides which means insects will eat the celery. When the insects start to eat the celery, the celery releases psoralen. This relates to Big Idea 3 (living systems store, retrieve, transmit, and respond to information essential to life processes) as the celery responds to predators by releasing psoralen to protect the celery from getting eaten. As organic farmers keep insects off the plant, the organic farmers guarantee poison in the plant.  Psoralen can also be found in other plants like figs, carrots, and parsley.

Research how psoralen damages the DNA structure and provide other symptoms humans can experience if they ingest psoralen. Also research the health benefits of eating organic figs, celery, carrots, or parsley. Then, take a position on whether or not humans should eat more organic psoralen-containing plants or eat more non-organic psoralen-containing plants providing evidence for your argument.

(Laura Gu, laugu4@students.d125.org)


2 comments:

  1. Psoralen damages the DNA structure by inducing phosphorylation of a histone called H2AX, which causes a sudden stop at the G1/S phase in Mitosis. This sudden halt prevents the cell from dividing and this causes a lower rate of cell creation. Phosphorylated, or something that has been phosphorylized, is define by the Campbell textbook as, when a molecule is covalently bonded to a phosphate group. All of this goes back to the cell unit where we learned about cell division via Mitosis, and how proper functioning Mitosis is essential to an organism.


    Some side effects of consuming psoralen include nausea and itchiness. As for the benefits of figs, celery, carrots, and parsley, dried figs provide numerous elements that our body needs, such as magnesium, calcium, iron, and potassium. Celery contains phthalides and polyacetylenes which are molecules that help detoxify carcinogens. Celery is also abundant with Vitamin C, which strengths blood vessel walls and helps absorb iron from the food we eat. Carrots give our body Vitamin A, which in its active form, beta carotene, helps strengthen eyes and is the basis for nutrition when it comes to "feeding the eyes". Parsley is rich in vitamins and dietary fiber, which help control blood-cholesterol, and protecting the human body from free radicals mediated injury and from cancers.


    In my opinion, I think that we should eat these vegetables, even if they are organically grown, because the nutrients that these vegetables offer outweigh the negative plant responses to being feed upon as they grow. My opinion was built upon the fact that conventional growers use pesticides to protect their crops from molds, insects and diseases. And when farmers spray pesticides, they can leave residues on produce. And this produce has a possibility of entering you and can potentially harm the eater.

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    1. Psoralen is commonly used in PUVA (Psoralen + ultraviolet light) treatments and naturally occurs in plants such as figs, carrots, and parsley. Psoralen can damage DNA by intercalating into DNA. Intercalation of DNA is when a molecule or group of molecules is included in between two DNA molecules or groups of DNA molecules. Additionally, according to the “Psoralen-Induced DNA Interstrand Cross-Links Block Transcription and Induce p53 in an Ataxia-Telangiectasia and Rad3-Related-Dependent Manner” article of “Molecular Pharmacology”, when Psoralen is exposed to ultraviolet light, covalent interstrand cross-links forms with thymines preferentially at 5'-TpA sites in the genome. These cross-links block DNA replication which causes apoptosis if the cross-links are not repaired. Psoralen can also cause greater sensitivity to light and increases the risk of getting skin cancer.

      Figs are a good source of dietary fiber, thus eating figs can lead to weight loss. Figs also help lower high blood pressure as figs are a good source of potassium which is a mineral that helps control blood pressure. Figs also contain calcium (around 79 milligrams in an 8 oz serving) which can strengthen bones and prevent them from thinning. Additionally, fig leaves have antidiabetic properties and can lower the amount of insulin a diabetic person needs.

      I agree with Anzori as I believe that eating organic psoralen-containing plants is better than eating non-organic psoralen-containing plants. Although both of these options have psoralen, organic plants are not grown with pesticides and other chemicals. To build off of Anzori's response, I found that, according to Dr. Joel Fuhrman in his book “Disease-Proof your Child”, pesticides and insecticides have been linked to causing cancers and illnesses like brain cancer, Parkinson's disease, multiple myloma, leukemia, lymphoma, and cancers of the stomach, prostate, and testes, Thus, I agree that the organic option is the lesser of the two evils as people will not have to suffer the possibilities of illness caused by harmful chemicals that are sprayed on non-organic plants.

      (Chris Yao, chyao4@students.d125.org)

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