Biology 3594A : October 20, 2011 - Hackenberg et. al

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tanhippopotamus305

15 Dec 2011

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Repetitive exposure to zinc oxide nanoparticles induces dna damage in. Look up more places in which you come in contact with zn-o-np and what companies are using it and marketing it: degradation of water pollutants, anticancer therapeutic (combined with uv radiation). They are useful drug carriers because these particles can get into cells and into the nucleus. This is because of their very small size: topical application, persistance - nano particles can be inert and not metabolized. Experimental design for the exam, make sure you know how to compare in vitro cell culture and mini organ cultures. In vitro cell culture: uses immortalized cell lines or primary culture (bodily fluids, not immortal). Dna fragmentation: tem and sem showed us the size, shape and location of zno-np, they"re going to make two different doses and have three different levels of treatment.

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Please paraphrase the following abstract:

The off-target distribution of anticancer nanoparticles to fibro- blasts creates a barrier to the effective treatment of desmoplastic tumors. However, we hypothesized that this nanoparticle detri- ment might be exploited to target the expression of secreted cytotoxic proteins from tumor-associated fibroblasts (TAF) as an anticancer strategy. In addressing this hypothesis, plasmids encoding the secretable TNF-related factor sTRAIL were loaded into lipid-coated protamine DNA complexes and administered by infusion in a murine xenograft model of human desmoplastic bladder carcinoma. Three doses were sufficient to generate approximately 70% of TAFs as sTRAIL-producing cells. sTRAIL

triggered apoptosis in tumor cell nests adjacent to TAFs. Fur- thermore, it reverted residual fibroblasts to a quiescent state due to insufficient activation, further compromising tumor growth and remodeling the microenvironment to favor sec- ond-wave nanotherapy. We confirmed the efficacy of this strategy in an orthotopic xenograft model of human pancreatic cancer, where the desmoplastic stroma is well known to be a major barrier to the delivery of therapeutic nanoparticles. Collectively, our results offer a proof of concept for the use of nanoparticles to modify TAFs as an effective strategy to treat desmoplastic cancers. Cancer Res; 77(3); 719â31. !2016 AACR.

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GENETICS QUESTION: For this experiment we focused on forward genetics: First, his- mutants were identified and then complementation analysis was used in order to determine which of the 7 his genes was mutated. ( The exact data can be seen at the bottom). In this experiment we screened for his- mutants that were generated via a random mutation process resulting from errors in DNA replication or induced by EMS aka Ethyl methanesulfonate. We compared a mutagenized culture that was treated with EMS and an un-mutagenized culture that was not treated with EMS. However, both cultures went trhough an enrichment process to increase the frequency of his- mutants.

Point mutations involve the substitution of one type of base pair for another. If the substitution replaces a purine with a purine (or a pyrimidine with a pyrimidine), it is called a transition. If the substitution replaces a purine with a pyrimidine (or a pyrimidine with a purine), it is called a transversion. Many mutagenic chemicals cause this type of mutation by alkylation of a nucleotide base. The chemically altered base can then be misread during replication or repair. For example the mutagen, ethyl methanesulfonate (EMS), adds an ethyl (-CH2-CH3) group to both guanine or thymine bases causing the modified guanine to pair with thymine and the modified thymine to pair with guanine.

1. Why might one gene be more susceptible to EMS mutagenesis than another gene?

2. Why might we have expected to find a higher frequency of polar mutants (his4A^-B^-C^-) in the unmutagenized culture compared to the mutagenized culture?

Table 2. Experiment 1B class data summary (number of his^-mutants by section) Unmutagenized
Section	1	2	3	*4ABC*	4A	4B	4C	5	6	7	*Total his^-* mutants**
Tuesday	7	1	5	4	2	1	9	2	3	1	35
Wednesday	2	1	14	0	4	2	2	4	8	2	39
Total	9	2	19	4	6	3	11	6	11	3	74
% each mutant	12.1	2.7	25.7	5.4	8.1	4.1	14.9	8.1	14.9	4.1	~100%

Mutagenized
Section	1	2	3	4ABC	4A	4B	4C	5	6	7	*Total his^-* mutants**
Tuesday	2	5	4	2	6	5	5	0	4	1	34
Wednesday	9	1	15	0	9	1	2	2	9	4	52
Total	11	6	19	2	15	6	7	2	13	5	86
% each mutant	12.8	7.0	22.1	2.3	17.4	7.0	8.1	2.3	15.1	5.8	~100%

*Please don't answer with photos, DO NOT UPLOAD PHOTO, it's hard to read.

I post this question twice, please don't answer this post if you already answer the other one, if you can answer different answer that's fine. REASON WHY I POST IT TWICE, I NEED TWO DIFFERENT VIEW.

Discussion

Hi All - this week you will learn about DNA - the molecule of life! You may think that protein-coding genes are the most important, but results from the Human Genome Project revealed that only about 2% of our DNA codes for protein - so what about the rest of the "junk DNA" (or non-protein coding portion of the genome) - is it functionally important? Yes! Scientists are learning how "the non-protein-coding portion of the genome is of crucial functional importance: for normal development and physiology and for disease". I would like you to please choose a topic with regards to the non-protein coding portion of the genome (this will introduce you to gene regulation which we will cover in chapter 11) or you may also choose to write about a topic that describes a mutation in any protein that is involved in DNA replication, transcription, or translation (we did not talk about all of the enzymes involved in those processes). Please list your reputable source - this is worth 0.5 pt (even if you use one of my sources below) and tell me WHY you chose your topic (this is worth 1 pt.) please try to briefly explain your topic to the best of your knowledge - I don't expect you to write a lot of detail about your topic - it might be hard to understand (which you are welcome to comment on in your paragraph)!

Examples to choose from (but not limited to) include: noncoding RNAs (snRNAs, miRNAs, siRNAs, snoRNAs, piRNAs, lincRNAs) and RNA therapeutics:

LIST:

1. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4119351/ (Development of microRNA therapeutics is coming of age)

2. http://www.umassmed.edu/rti/ (RNA Therapeutics Institute)

3. http://www.genengnews.com/insight-and-intelligence/rna-based-therapeutics-and-vaccines/77900520/

4. http://genesdev.cshlp.org/content/26/21/2361.full (Biology of PIWI-Interacting RNAs: new insights into biogenesis and function inside and outside of germlines)

5. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4265212/ (PIWI proteins and their interactors in piRNA biogenesis, germline development and gene expression)

6. http://www.news-medical.net/news/20121203/microRNAs-play-an-important-role-during-embryonic-development.aspx

7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4578617/ (the role of microRNAs in cell fate determination)

8. http://news.berkeley.edu/2017/01/13/scientists-reprogram-embryonic-stem-cells-to-expand-their-potential/

9. http://www.the-scientist.com/?articles.view/articleNo/40871/title/The-Second-Coming-of-RNAi/

10. http://web.mit.edu/newsoffice/2013/cardiac-development-needs-more-than-protein-coding-genes-0124.html (long non-coding RNA molecules)

11. http://www.alzforum.org/news/research-news/new-role-micrornas-torpedoes-sink-neurons(microRNAs)

12. http://ghr.nlm.nih.gov/condition/rothmund-thomson-syndrome (mutation in human helicase gene)

13. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3633371/ (mutation in mitochondrial helicase gene called TWINKLE)

14. http://sfari.org/news-and-opinion/news/2013/in-autism-related-disorders-rna-turns-out-to-be-key (RNA topoisomerase)

15. http://ghr.nlm.nih.gov/gene/TERC (dyskeratosis congenita - mutations in the TERC gene - the RNA component of telomerase)

16. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3853347/ (Top3beta is an RNA topoisomerase that works with Fragile X syndrome protein to promote synapse formation)

The following 3 articles discuss long non-coding RNAs - there are many examples in each article so you only need to talk about one example - not the whole article:

1. http://www.sciencedirect.com/science/article/pii/S2468054016300063 (mechanism of action and functional utility)

2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5084630/ (dysregulated expression in ovarian cancer)

3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4736767/ (stem cells)

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Biology 3594A : October 20, 2011 - Hackenberg et. al

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