Acting and reacting in life science biotechnologies
For more than 2 years now, the Silicon Rhodamine-like (SiR) technology has allowed the live cell imaging field with fluorescence microscopy to evolve significantly.
Fluorescent SiR-probes have appeared as the best alternative tools for studying Actin (SiR-actin), Microtubules (SiR-Tubulin), DNA (SiR-DNA) and now lysosome (SiR-Lysosome) for live cell imaging. Who better to show this? Well, here’s how other researchers have been using them to get optimal results. [Read more…]
The Silicon Rhodamine-like (SiR) technology has significantly contributed to the recent development of DNA and cytoskeletal analysis by live cell imaging.
In 2014, two new Silicon Rhodamine-like (SiR) fluorescent probes were released for studying actin & tubulin by live cell imaging. SiR-Actin and SiR-Tubulin are fluorescent probes compatible with most microscopes (including super-resolution settings) that directly stain actin & tubulin without the need to transfect cells with vectors expressing fluorescently labeled Actin or Tubulin. The two original dyes were successfully followed by a new SiR-DNA probe in order to visualize DNA in living cells.
The existing SiR stains have a λabs of 652 nm and a λem of 674 nm to be used with the Cy5 filter (Fig 1).
However, the continuously growing number of researchers using these stains asked us whether stains with different biophysical properties would be made available. In other words, they were asking “is there another colour to allow for double staining e.g. of Actin and Tubulin in living cells?”
In this post, I’d like to take a look at the current understanding of tubulin PTMs, that include tyrosination/detyrosination, Δ2-tubulin formation, acetylation, phosphorylation, ubiquitination, glutamylation, and glycylation. This is inspired by contribution provided by Cytoskeleton Inc., who are experts in this domain.
Fig 1: Structure of FtsZ protein determined by X-ray crystallography (4) and oligomeric structure arranged from the monomer (5).
The unprecedented increase in antibiotic-resistant pathogens and lack of new antibiotic development highlights the need for new anti-microbial drugs active against novel targets such as bacterial cell division proteins. Recently, FtsZ (Filamenting temperature sensitive mutant Z) has become the focus of antibiotic research as a novel target for new anti-microbials (1, 2). [Read more…]
In the autumn of 2014, we presented new stains to conduct live cell imaging of Actin and Tubulin, which I covered in my post 2 new Actin and Tubulin live-cell imaging stains – without transfection!
Fig 1: Live MCF10A cells spheroid stained with SiR-DNA and imaged by confocal microscopy. Courtesy of C. Conrad and K. Jechow (Heidelberg).
SiR-Actin and SiR-Tubulin exhibit a number of benefits which have since then be experienced by a huge number of labs all over the world:
Since then, Spirochrome has added another stain with the same benefits: SiR-DNA, a far-red, fluorogenic, cell permeable and highly specific probe for DNA (see Fig 1).
From June 27th to June 29th, the SLAS – High Content Screening Conference took place in Dresden/Germany. The conference focussed on new essays and novel microscopy techniques.
Spirochrome and tebu-bio were selected to present a poster about the features of SiR-stains, which are excellent tools for phenotypic screening and high content screening (HCS) approaches.
If you are interested in learning more about these exciting live cell imaging tools, don’t hesitate to download our joint poster:
Any questions or comments? Please feel free to contact me with the form below!
Interested in learning more about tools like this?
Fig 2: Structure of microtubules
Recently, I issued a post about a method which allows measuring microtuble binding capabilities of proteins of interest. Today, I invite you to look at methods for measuring the dynamic polymerisation of tubulin to microtubules and to detect the impact of compounds or other variables in your experiments on this process.
Fig 1: Electron micrograph of microtubules (100,000x)
Tubulin represents one of the major cytoskeleton structures. It plays an important role in cell structure, intracellular transport, and mitosis. In eukaryotic cells, tubulin polymerizes to form structures called microtubules (MTs) (Fig. 1). When tubulin polymerizes it initially forms proto-filaments, MTs consist of 13 protofilaments and are 25nm in diameter, each um of MT length is composed of 1650 heterodimers. Microtubules are highly ordered fibers that have an intrinsic polarity, shown schematically in Figure 2. Tubulin can polymerize from both ends in vitro, however, the rate of polymerization is not equal. It has therefore become the convention to call the rapidly polymerizing end the plus-end of a microtubule and the slowly polymerizing end the minus-end. In vivo, the plus end of a microtubule is distal to the microtubule organizing center.
[Read more…]
You suspect your protein binds to microtubules? That it might stabilize or destabilize these filamentous structures? Then this post is here to help you to find a meaningful assay to validate your assumption. [Read more…]
For one year now,  SiR-Actin and SiR-Tubulin, the second generation of tools to stain actin and tubulin in living cells, have been available on the market – and although it may sound like an overstatement, these stains have changed the world of Live Cell Imaging. [Read more…]
Colchicine chemical structure (64-86-8).
Microtubules are key components of the cytoskeletal structure of eukaryotic cells. Composed of alpha- and beta- tubulin sub-units, microtubules are dynamic entities with pivotal cellular roles (e.g. division and mitosis). Because of these unique characteristics, the first microtubule-based anti-cancer drugs have been described in the early 70’s. Here, we will review the 6 most popular small compounds active on tubulin polymerization and microtubules which are regularly used in today’s microtubule-centred in vitro assays.
Taxol chemical structure (33069-62-4).
Looking for pure small molecules active on Microtubule and compatible with in vitro studies?
tebu-bio’s experts have selected high quality sources of active small molecules. Discover those related to tubulin and Microtubules right here.