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Prof. Fahd M. Nasr

Faculty of SciencesLebanese University

Beirut, Lebanon

https://yeastwonderfulworld.wordpress.com/

Biol328 - B3212Molecular

BiotechnologyLecture 2

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Biotechnology• Term first coined in 1917 by Karl Ereky Large scale production of pigs using sugar

beets as food source Making products from raw materials with

the aid of living organisms• In 1961 redefined as the industrial

production of goods and services by processing using biological organisms, systems and processes

A MORE COMPLETE DEFINITION

Using modern technology to change or modify, with the goal of improving, the

biological structure of living organisms or to create new organisms, for specific positive uses and/or to provide beneficial processes,

products, or services to consumers/businesses/society

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• Upstream processing Preparation of raw

material Fermentation and

biotransformation Use of bioreactor

• Downstream processing Recovery and

purification from the medium or cell mass

Bioengineered Biotechnology Process

Bioengineering Processes• Identification and isolation of cells to be cultured• Determination of optimum culture and harvesting

systems• Scale-up to large batch or continuous bioreactors• Down-stream processes for fractionation, extraction,

purification and sterilization• Methods for process control and product quality• Protocols to ensure safety and containment

throughout development and production

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Biotechnology• In the 1960’s and 1970’s focused primarily on

improving upstream processing, bioreactor design and downstream processing

• New strains created by mutation and screening• Very successful for antibiotic production

• Everything changes with development of recombinant DNA technology• New organisms for production (transfer production to

new species)• Quantity production of molecules normally present at

miniscule levels

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Golden Rice grains

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Potential Benefits From Biotechnology

• More accurate disease diagnosis and treatment

• Improve crop yield, disease and stress resistance

• Microbial production of chemicals, enzymes, food

additives, pharmaceuticals, polymers, etc.

• Livestock with enhanced genetic attributes

• Elimination of pollutants and waste materials

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Potential Social Concerns and Consequences of Biotechnology

• Organisms harmful to other organisms or environment

• Organisms reduce natural genetic diversity• Genetic engineering of humans?• Genetic privacy issues• Limited availability to poorer nations• Undermine traditional agricultural practices• Quest for profit undermines free exchange of

knowledge

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Streptomyces• Extremely large group of organisms distributed

worldwide– Species rarely pathogenic– Occasional cases of mycetoma

• Members produce antibiotics more than 90% of the therapeutically useful antibiotics– First streptomycin and actinomycin– Since 1940 over 500 different antibacterial

compounds

Representative sources of antibiotics

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Bacillus thuringiensis (Bt)• Bacterium that produces a protein called

Bt toxin, a biological insecticide• Inserting a copy of the Bt gene into plants

enables them to produce Bt toxin protein Such plants can resist some insect pests

• Bt crops: crop plants that contain genes for Bt toxins (Bt Cotton)

Cell wall in Gram-positive bacteria

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Gram-positive Bacterial Secretion Pathways

SRP-independent pathwaySRP-dependentpathway

Cell wall in Gram-negative bacteria

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Gram-negative Bacterial Secretion Pathway

Type II

Types I, III

Eukaryotic Secretion Pathway

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Fundamental in Mol. Genetics

• Chemical Structure of a Nucleotide• Flow of information

– DNA Replication– Transcription– Translation

• RNA molecules secondary structure• Eukaryotic and prokaryotic genes

Genetic code

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Codon usage• Codons for the same aa different frequencies

Codon usageE. coli Human

Alanine 524,410 codons1542 genes

1,145,022 codons2681 genes

GCU 14% 27%GCC 36% 42%GCA 16% 21%GCG 34% 10%

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Codon usage• Codons same aa

– Different frequencies

– Correlation between codons and tRNAs

• Regulation of gene– Correlation between transcription and

codon usage

– Rare tRNAs delay translation

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Transcription in Eukaryotes• More comlex

– Metabolic activity– Cell division– + Embryonic development– + Cell differentiation

• Each gene has a set of regulatory sequences– Basic or core GTFs– RE or UE TFs

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Initiation at RNA Pol. II promoter

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RNA Pol. II promoters• Core promoter (TATA, Inr, DPE, etc.)• UE (short sequences or modules)

– GC box = GGGCGG SP1 150kD– Octamer = ATTTGCAT

Oct1 (76kD) and Oct2 (52kD)– NF-kB = GGGACTTTCC

NF-kB (heterodimer 50kD + 65kD)Cell survival

RNA Pol. II promoters• Response Elements (RE)

– Heat Shock Elements (HSEs)– Upstream of genes induced by

temperatureCNNGAANNTCCNNGHSTF (93kD)

– Some genes have various modules and REMultiplicity of regulatory influences

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Transcriptional control modules

The end