Term
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Definition
| a diverse group of ring structures with biosynthesis similar to fatty acid biosynthesis |
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Term
| How are polyketide synthase genes ordered on the genome of producing organisms? |
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Definition
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Term
| Identify two enzyme subunits in the polyketide synthase biosynthesis- |
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Definition
ACP (acyl carrier protein subunit)
KS ( ketosynthease subunit) |
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Term
| Provide 5 examples of tetracyclines, polyketide derived antibiotics |
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Definition
1. 7-chlortetracycline (aureomycin)
2. 5-oxytetracycline (terramycin)
3. 6-demetythl- 7-chlrotetracycline (declomycin)
4. 6- deoxy-5-hydroxytetracycline (doxycycline)
5. 7-dimethylamino-6 dimethyltetracycline (minocycline) |
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Term
| Tetracyclines ___ protein synthesis and are _____ |
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Definition
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Term
| macrolides such as ___ are polyketides derived from either ___ or ___ |
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Definition
| erythromycin, acetate, propionate derived polyketide |
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Term
What are properties of erythromycin A?
Ring size and comments |
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Definition
Ring size 14
comments: original 14-membered macrolide antibacterial agent |
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Term
| What are properties of azithramycin? |
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Definition
ring size 15
zithromax
orally active azalide, semisynthetic analogue or erthryomycin |
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Term
What is avermectin?
ring size and comments |
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Definition
ring size 16
veterinary use; also use to treat human onchocerciasis (river blindness) |
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Term
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Definition
ring size 16
mutational biosynthetic analogue of avermectin, antiparasitic |
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Term
| ethryomycin mode of action: |
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Definition
| binds to the ribosome polypeptide tunnel |
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Term
| Explain the function (precursors) incorporated into erythryomycin |
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Definition
1. feed glucose
2. feed dextrins
3. feed soybean oil - polyketide synthatse starts with C2s |
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Term
| Why is Erythromycin produced in E.coli? |
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Definition
1. to learn how to improve production in the native host used in manufacturing - Saccharopolyspora erythraea
2. e coli is technically convenient
3. step wise introduction biosynthetic cluster into E. coli (10 year effort) producing only 0.6 mg/L (> 10 g/L in production strains)
4. alternative e. coli strains with enhance biosynthetic precursor supply utilized
5. e. coli strains with altered deoxysugar glycosylation capabilities evaluated- why is this glycosylation important?
Goal : to predict how to further improve erythromycin A production by precursor flow, altering polyketide biosynthesis, optimization of erythronolide B (EB) 3- mycarosyl erthronolide B (MEB) formation
* however, erythromycin A production in E. coli is genetically unstable |
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Term
| What is the goal of engineering erythromycin A? |
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Definition
| to predict how to further improve erythromycin A production by precursor flow, altering polyketide biosynthesis, optimization of erythonolide B (EB) 3- mycarosyl erthronolid B (MEB) formation |
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Term
| What is a disadvantage of using E. coli for engineering erythromycin A production in surrogate host |
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Definition
| erythromycin A production in E. coli is genetically unstable |
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Term
| Non-ribosomal peptide (NRPS) antibiotics are synthesized by PKS, also known as ____, which are cyclic peptides product by ____ |
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Definition
bacitracins
bacillus licheniformis |
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Term
| Provide 6 approaches (traditional or genomic) for antibiotic strain and yield improvement |
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Definition
1. medium optimization (signal molecules, overcoming carbon, nitrogen or phoshate repression, repression of synthetase repression)
* Mutagenesis and selection, resistance to high levels of the antibiotic
3. identification of resistance genes, often adjacent biosynthetic genes
4. deregulated mutants- cloning of positive regulatory factors, generation of blocked mutants
5. evaluation of new hosts, new promoters, pathway specific transcription factors, increased gene dosage
6. gene and pathway shuffling to produce New structures |
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Term
| Continuous strain improvement (CSI) increases_____ and _____ while reducing ____ |
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Definition
fermentation yield
stability
manufacturing cost |
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Term
| strain development and enhanced stability have been accelerated by ___, ___-, and ______-- |
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Definition
| genomic, regulatory network, and pathway engineering methods |
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Term
| When can the production of antibiotics not be stable? |
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Definition
| not stable during scale-up (titer decreases) |
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Term
| What components are needed for complex media optimization? what type of fermentation process is typically utilized? |
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Definition
1. carbon, nitrogen, trace metals, and phosphate sources that do not repress transcription of antibiotic biosynthetic genes (enzymes) are needed
Fed batch |
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Term
| During carbon catabolite regulation of antibiotic biosynthesis, what is the interfering carbon source and non-interfering carbon source for penicillin? |
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Definition
interfering carbon source- glucose
non interfering carbon source lactose |
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Term
| What is the purpose of biosynthesizing toyocamycin in this case? |
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Definition
it changes the levels of intracellular and exogenous guanine and adenine levels
they are false feedback inhibitors azaguanie |
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Term
| What two types of media are used in process development? |
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Definition
1. production
2. synthetic |
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Term
| What is the role of soy oil in the production medium? |
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Definition
| add acetate units as a precursor as well as an energy supply |
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Term
| What effect does the impeller tip velocity and temperature have on toyocamycin titer? |
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Definition
| lower speeds and higher temperatures increased titer and yield |
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Term
| Many media components are ____ that control antibiotic biosynthesis; therefore, a wide range of media is needed for _____ |
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Definition
regulatory factors
antibiotic discovery |
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Term
| Give 4 examples of regulators of antibiotic biosynthesis genes. what can improve antibiotic yields? |
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Definition
1. homoserine lactone
2. butyrolactone
3. A-factor
4. quorum sensing signals
Over production or altered expression of quorum sensing singal molecule biosynthesis pathway genes or pathway specific transcription factors can improve yield |
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