Biotechnology Terms Starting With E
Biotechnology Glossary: E
Jump to Biotechnology Term
Electroporation
/ eh-lek-troh-por-AY-shun / · Greek elektron, amber; Latin porus, pore
Electroporation is a technique that uses brief, controlled electrical pulses to transiently permeabilize cell membranes, allowing nucleic acids, proteins, or other molecules to enter cells.
The electrical pulse creates temporary hydrophilic pores in the lipid bilayer that reseal within milliseconds, enabling uptake of exogenous molecules without permanent cell damage if parameters are optimized. Optimal voltage differs substantially between cell types: bacterial cells typically require around 2,500 volts per centimeter, while mammalian cells need only 100 to 500 volts per centimeter because of their larger size and more sensitive membranes. Electroporation is used for plasmid transfection, CRISPR guide RNA delivery, and siRNA introduction in both cell culture and in vivo applications.
Clinical researchers have also applied it to deliver DNA vaccines and chemotherapy drugs directly into tumor tissue during electrochemotherapy.
Electroporation of CAR-T cells has emerged as a non-viral method for delivering CRISPR components to edit T cell genomes before infusion into cancer patients. In one 2020 clinical trial at the University of Pennsylvania, researchers electroporated patient T cells with ribonucleoprotein complexes to knock out three genes simultaneously, producing edited cells that persisted in patients for up to nine months.
Electroporation always kills cells. When voltage, pulse duration, and buffer conditions are optimized for a given cell type, the majority of cells survive, reseal their membranes, and resume normal growth within hours of the pulse.
Researchers use electroporation to introduce plasmid DNA into Escherichia coli at efficiencies exceeding 10 billion transformed colonies per microgram of DNA, far higher than chemical transformation methods. Surviving cells replicate the plasmid and express any encoded gene of interest within hours.
E-coli →Embryo Transfer
/ EM-bree-oh TRANS-fer / · Greek embryon; Latin transferre, to carry across
Embryo transfer is the procedure of moving an embryo from a donor organism or an in vitro fertilization dish into the uterus of a recipient female for continued development.
In livestock production, embryo transfer allows genetically superior donor cows to produce multiple offspring per year by flushing embryos and implanting them in lower-value recipient cows. A single high-merit dairy cow can yield 6 to 10 viable embryos per flush cycle, compared with the single calf she would otherwise produce annually. In human assisted reproduction, IVF-derived embryos are transferred to the uterus or cryopreserved in liquid nitrogen at minus 196 degrees C for later use.
Conservation programs have used the technique to transfer embryos of endangered species, such as the bongo antelope, into related domestic species acting as surrogates.
The northern white rhinoceros (Ceratotherium simum cottoni) is functionally extinct in the wild, with only two females remaining. Scientists have created hybrid embryos using eggs from these females and frozen sperm from deceased males, with plans to transfer resulting embryos into southern white rhinoceros surrogates as a last-resort conservation strategy.
Reproductive System Fun Facts →Embryo transfer changes an embryo's genetic makeup. The procedure only moves the embryo from one location to another and does not alter its DNA in any way.
In the conservation program for the black-footed ferret (Mustela nigripes), embryos produced by artificial insemination have been transferred into domestic ferret surrogates to increase the number of offspring born each breeding season. Litter sizes from transferred embryos have averaged three to four kits, helping rebuild a population that had dropped to fewer than 20 individuals in the 1980s.
How To Become A Perinatologist? →Enzyme Engineering
/ EN-zym en-jih-NEER-ing / · Greek en, in; zyme, leaven; engineer
Enzyme engineering is the modification of enzyme structure by rational design or directed evolution to improve catalytic activity, substrate specificity, or stability, or to create entirely novel catalytic activities not found in nature.
Rational design uses structural biology and computational modeling to predict amino acid substitutions that improve enzyme properties, while directed evolution mimics natural selection by randomly mutating and screening large enzyme libraries for improved variants. Frances Arnold won the 2018 Nobel Prize in Chemistry for pioneering directed evolution, having used iterative rounds of mutagenesis and selection to produce enzymes that catalyze reactions, such as carbon-silicon bond formation, with no natural precedent. Engineered enzymes now operate at temperatures exceeding 90 degrees C, pH values below 4, and in organic solvents that would denature most natural proteins.
These properties have made them indispensable in pharmaceutical synthesis, biofuel production, and food processing.
Engineered cytochrome P450 enzymes developed in Arnold's laboratory can insert carbene groups into carbon-hydrogen bonds with selectivities exceeding 99% enantiomeric excess, a transformation that previously required expensive precious-metal catalysts and generated significant chemical waste. This single advance opened an entirely new class of green chemistry reactions.
Are Enzymes Proteins? →Natural enzymes are always better suited for industrial use than engineered ones. Engineered enzymes can outperform their natural counterparts at high temperatures, extreme pH, or with substrates that natural enzymes cannot bind.
Engineered subtilisin proteases used in laundry detergents such as those produced by Novozymes remain active at 60 degrees C in alkaline wash water at pH 9 to 10, conditions that rapidly inactivate the wild-type bacterial enzyme from which they were derived. Directed evolution introduced mutations that stabilize the active site against thermal unfolding while preserving catalytic efficiency against protein stains.
Expression System
/ ek-SPRESH-un SIS-tem / · Latin expressio, a pressing out; Greek systema
Expression System is a combination of host organism and molecular tools, including an expression vector, promoter, and regulatory elements, used to produce recombinant proteins at high levels.
Common expression systems include Escherichia coli, yeast, insect cells using baculovirus vectors, and mammalian cells such as Chinese hamster ovary (CHO) cells. The choice of system depends on protein size, required post-translational modifications, intended application, and cost constraints. E.
coli can produce milligram quantities of simple proteins within hours, but it lacks the glycosylation machinery needed for many therapeutic proteins. Transient expression generates protein within days, while stable cell lines provide consistent, scalable manufacturing for commercial biopharmaceuticals.
The baculovirus-insect cell system, commonly using Spodoptera frugiperda (Sf9) cells, can produce up to several hundred milligrams of recombinant protein per liter of culture, making it a preferred platform for producing virus-like particles used in vaccines such as the FDA-approved Cervarix HPV vaccine.
Recombinant Proteins →Any gene placed into a new host will produce a functional protein. Promoter compatibility, codon usage bias, protein folding requirements, and the host's post-translational modification machinery all determine whether a protein is produced correctly.
Pichia pastoris (now reclassified as Komagataella phaffii), a methylotrophic yeast, produces recombinant human serum albumin at concentrations exceeding 10 grams per liter of culture. This level of output far exceeds what E. coli typically achieves for the same protein, illustrating how host choice directly shapes yield.
Yeast →