News & Press

When to Passage Sf9 Cells

An important factor in baculovirus expression is assessing when to passage Sf9 cells, which are commonly used to make recombinant viruses or for protein production.  In our last blog we talked about how to make the transition from monolayer to suspension cultures and how maintain cells in a healthy state during this time. To define what is meant by ‘healthy’ cells,  Figure 1 shows a sample of healthy Sf9 cells

Suspension Sf9 Cells from Monolayer Cultures

The transition to suspension Sf9 cells from monolayer cultures is not difficult but does depend on harvesting the attached cells at the right time. Too early and it is extremely hard to detach the cells from the culture flask. Too late and the cells will be in such poor condition that they may not recover when in suspension. Trying to describe in words how the monolayer culture should look prior

Product Launch – pOET8!

November marks the welcome of OET’s newest product – the pOET8 baculovirus transfer vectors (pOET8.VE1; pOET8.VE2; pOET8.VE3).  Compatible with any baculovirus expression system, including our own flashBACTM technology, the new range of pOET8 vectors are proven to help increase recombinant protein production in insect cells. The increased yield is achieved by allowing co-expression of foreign genes with a vankyrin expression cassette.  This gene cassette comprises the Campoletis sonorensis ichnovirus P-vank-1 protein

baculoQUANT titration of recombinant baculoviruses

There are many methods available for the titration of recombinant baculoviruses.  One of the most convenient is the use of the quantitative polymerase chain reaction (QPCR), which assesses how much virus DNA is present in a freshly-amplified stock.  This is compared with a standard curve derived from a control virus stock to give an infectious titre expressed as Q plaque forming units (pfu) per millilitre.  OET Ltd market the baculoQUANT™

Reviving Cells from Liquid Nitrogen

The process of reviving cells from liquid nitrogen, or indeed from transport on dry ice, can be a little difficult on occasion.  Two events at OET recently have highlighted this. Firstly, we received a new cell line that came with a very complicated procedure for its culture – it is a mammalian species, quite different from your run of the mill HeLa’s and HEK293’s.  Its culture is known to be

Co-infection with Baculovirus Vectors for Multiple Protein Expression

A question that comes up from time to time is the use of co-infection with baculovirus vectors for multiple protein expression in insect cells.  The need arises if you have produced a number of baculovirus vectors that each synthesise a component of a multi-subunit complex, such as an enzyme or a virus like particle.  Intuitively, you know that it is probably necessary to add many virus particles per cell to

Baculovirus Transfer Vectors Compatible with flashBAC™

A question we are asked from time to time is to identify baculovirus transfer vectors compatible with our flashBAC™ system. We obviously nominate our own extensive range that is available but frequently someone has an old plasmid from years ago that they want to reuse. Originally they may have paired it with a linear DNA system such as BaculoGOLD or BacPAK6 or even wild type DNA where recombinant virus selection

Variable Expression of Multi-Component Protein Complexes

Variable expression of multi-component protein complexes is increasingly necessary as more sophisticated projects are attempted.  But how can this be achieved?  Most of our expression work is based on the baculovirus system, in particular our flashBAC™ vectors that permit easy recombinant virus generation in a one-step process.  These insect-specific viruses offer an ideal platform for producing a wide range of recombinant proteins including nuclear, cytoplasmic, membrane-bound and secreted examples. But

Intermediate scale recombinant protein production

Between initial tests and larger scale up you may want to conduct intermediate scale recombinant protein production using baculovirus vectors.  If you are working with several constructs then this can begin to get expensive of cell culture vessels such as the ubiquitous 125ml conical flasks, in which you can amplify 25-30mls of virus-infected cells.  Space on shakers can also be at a premium in some labs. To address both the

Expression Systems insect cell culture media

OET is pleased to offer a wide range of Expression Systems Insect cell culture media, from the very popular ESF 921, to specialized insect transfection media. Expression Systems’ media are easy to adapt your cells into and the insect specific media gives great protein yield, when compared to rival media.   ESF921 insect culture media OET use ESF 921 for all in-house work, due to it’s high performance record, whilst

Adapting insect cells to a new growth medium?

Have you ever had the experience of adapting insect cells to a new growth medium?  We recently had to do this for a client project because they had used a particular medium previously and were keen to maintain the same conditions to continue the work with us. This process made us realise that switching to a new serum-free insect cell culture medium can result in short term stress responses in

flashBAC 5+1 offer

OET’s flashBAC 5 reaction kit ranges are some of our most popular products. However, recent feedback has revealed that some customers are reluctant to make use of the positive control transfer vector as this sacrifices 1 reaction and so reduces the number of their own viruses that they can produce. In recognition of this issue, until further notice, we are increasing the amount of flashBAC DNA in all of our

Quick guide to plaque assays

Quick guide to plaque assays of baculovirus infectivity.  Last week we ran a short training course on baculovirus expression vectors.  As part of this we put together a one page guide for carrying out plaque assays.  This might be useful to those of you looking for something you can have on the lab bench while conducting your own plaque assays.  We have added a image of one of our 12-well

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