Welcome!

Oxford Expression Technologies are the experts when it comes to the science of baculovirus. For almost 10 years now we have specialised in recombinant protein production in insect cells and the ‘Bac to the Future’ blog is the culmination of this extensive knowledge.

Written by our in-house scientists, articles cover every aspect of the baculovirus system – from its discovery and background, to practical applications in research and industry. We cover both the day-to-day challenges and more complex cases faced by ourselves and customers. You can also keep up to date on all the news, developments and promotional offers from the company.

If you have a question about any of the content featured, or simply want more information on a particular topic, then do not hesitate to get in touch with us directly at info@oetltd.com. In addition, OET offers everything needed to aid your own insect virus research. As creators of the world renowned flashBACTM technology, our range of baculovirus expression vectors are designed for simple and rapid recombinant protein production. This is supported by an optimised range of transfer plasmids, transfection reagents, and cell culture media to ensure a powerful and versatile system. Browse the full collection of products at https://oetltd.com/shop/

We hope you enjoy.

-OET

Introduction to the Baculovirus Expression System

Baculoviruses are in many respects an odd choice for use as an expression system to make recombinant proteins.  In their natural environment they infect insect larvae/caterpillars, which frequently results in the death of the host and its reduction to a puddle of progeny virus (Fig. 1).  They are also unusual in that they produce two structurally different forms in their life cycle. The first is a lipoprotein-enveloped particle that buds from virus-infected cells and spreads infection throughout an insect.  Subsequently, virus particles are occluded within an abundant protein (polyhedrin) in the nuclei of infected cells to form polyhedra (Fig. 2). This form of the virus acts as a dispersal agent for the virus between susceptible hosts in the field. (more…)

Insect Cell Culture Media

Following on from our last blog we briefly describe insect cell culture media.  It used to be that all animal cell cultures depended on the addition of calf serum to a basal medium to ensure growth.  Insect cells were no exception, although it always seemed a little odd that mammalian serum could aid their propagation.  While insect cells were only used in basic research for the study of insect viruses this didn’t matter too much, although the maximum densities obtained were rather limited (up to 2-3 x 106 cells/ml). (more…)

Culturing Insect Cells

On a scale of complexity/difficulty, culturing insect cells falls somewhere between yeast and mammalian systems. They can be grown in suspension or as monolayer cultures.  However, the latter format does not require trypsin enzyme treatment prior to harvest and sub culture or passage.  Further, the growth medium does not require the use of carbon dioxide to regulate the pH as is the case in many mammalian monolayer cultures.  Unlike yeast, insect cells are sensitive to over dilution when setting up new cultures and can decline very rapidly if grown to high densities. (more…)

Selecting a Protein Expression System

A major decision facing anyone starting a new project requiring any quantity of recombinant protein is selecting a protein expression system. A quick search online will unearth a large number of options and an often bewildering choice of different vectors to use within any given system. For the novice, this can be daunting!

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Baculovirus P10 Structures and Role in Insect Cells

A blog on baculovirus P10 structures and the role in insect cells might appear a slightly odd topic for a blog from a company based on expression of recombinant proteins. However, a recently published paper that is the product of a collaboration between the Insect Virus Research Group at Oxford Brookes University and OET Ltd offers some insight to the role of P10 structures in infected insect cells and why our flashBAC ULTRA vector is so successful (Graves et al., 2019). flashBAC ULTRA, like all other versions of this expression vector, offers a one-step process for making recombinant viruses but lacks several of the baculovirus genes, including p10. (more…)

New pOET9 Vectors!

This month we’re celebrating the release of our newest product to come out of the OET labs – pOET9 transfer vectors. With the application of baculoviruses in mammalian protein expression becoming increasingly popular it seemed only right to introduce a new set of transfer vectors that will facilitate the production of recombinant proteins in mammalian cell lines using Autographa californica nucleopolyhedrovirus. (more…)

Plaque-Assay Schematic

We’ve said it enough times; the plaque-assay is the ‘gold standard’ for determining virus infectivity. But this doesn’t make the procedure any easier! Whether it’s the agonising 5 day waiting period or the disorientating number of steps, plaque-assays can seem like a chore and we’ve heard of more than enough non-virologists admit to skipping this laborious technique in favour of a simpler solution. (more…)

How to Grow Cells over the Holiday Period

We want to talk about how to grow cells over the holiday period spanning Christmas and New Year.  (OK, so we have covered this before but we think it is worth repetition for new users of the baculovirus-insect cell system).  Most labs, academic and industry, will have some time off over the next few weeks. It is often a problem keeping your cell cultures in good condition so that when you return in 2019 you can pick up that important protein expression project without too much delay.  Given that most insect cells (usually Spodoptera frugiperda or Trichoplusia ni cell lines) need to be sub cultured at least twice a week if they are grown as suspension cultures, how will they survive for this protracted period? (more…)

Growing Mammalian Cells Successfully

While OET Ltd has built its reputation on baculovirus-insect cell expression systems, we also undertake work that requires growing mammalian cells successfully too.  Much of this work involves the transduction of these cells with BacMam vectors to express genes placed under the control of mammalian-specific promoter elements.  Some of our work in this area was recently published and involved the generation of improved BacMam vectors for transducing both mammalian cells in culture and also human pancreatic islet cells for pre-clinical tests of gene therapy.  (more…)

Growing insect cells successfully – Part II

In our previous blog we talked about the early stages of growing insect cells when you might just have revived a frozen stock and set up either monolayer or suspension cultures (or both).  If you have established a viable suspension culture – and here we are talking primarily about insect cells such as Sf21 or Sf9 – you will probably monitor them fairly closely for their rate of growth.  The ideal scenario is that your cells will double in number every 24 hours.  However, frequently this isn’t the case.  Why not? (more…)