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Super-sectioning with multi-sheet reversible saturable optical fluorescence transitions (RESOLFT) microscopy

Scientists at the KTH Royal Institute of Technology in Stockholm Sweden, in collaboration with Calico Life Sciences, a biotechnology company founded by Google’s parent company Alphabet Inc., have made significant strides in cellular imaging. The work, published in the prestigious academic journal Nature Methods in May 2024 highlights the development of a new method called multi-sheet RESOLFT (reversible saturable optical fluorescence transitions) microscopy, which was achieved with the help of a specialized Cobolt 06-MLD laser. This innovation promises to revolutionize the way we observe and understand subcellular structures in living cells.

The technique improves upon traditional light-sheet fluorescence microscopy (LSFM) by enabling the imaging of fine subcellular details with minimal photodamage and higher speed. By using reversibly switchable fluorescent proteins (RSFPs) and a periodic light pattern, the group was able to generate multiple ultra-thin emission sheets. This method allowed for rapid volumetric imaging, capturing high-resolution images of subcellular structures in living cells.

The Cobolt laser’s precision was instrumental in producing these thin light sheets, crucial for the super-resolution imaging that the study achieved. The laser’s stability and ability to maintain consistent illumination were key factors that enabled the researchers to observe cellular processes such as cell division and actin motion in real-time.

A Step Forward in Imaging Technology

This advancement is not just a technical marvel for academic laboratories but holds significant implications for medical and biological research. By enabling detailed, rapid, and minimally invasive imaging of living cells, the multi-sheet RESOLFT technique can enhance our understanding of cellular processes such as cell division, cytoskeleton dynamics, and virus particle movements. This could lead to better diagnostic tools, improved treatments for diseases, and a deeper understanding of fundamental biological processes.

The team’s success demonstrates the potential of integrating advanced laser technology with innovative imaging techniques. With the Cobolt 06-MLD laser, scientists can now achieve volumetric imaging at unprecedented resolutions, opening new frontiers in the study of life at the microscopic level.

Super-resolution Imaging Unveils the Self-replication of Tau Aggregates Upon Seeding

Dementia is one of the major causes of disability among older people affecting 50 million people worldwide. Alzheimer’s disease (AD) is the most common form of dementia, characterized by extensive neuronal loss and severe brain shrinkage. As experts have noted, this pathology is driven by the accumulation of extracellular amyloid-beta (Ab) plaques and intracellular hyperphosphorylated tau aggregates. As it turns out, in Alzheimer’s disease, an abnormal form of tau accumulates and begins sticking together in thread-like structures called neurofibrillary tangles. These tangles are not effectively disposed of through the cell’s usual ways of removing “trash.” As a result of this build-up the microtubule superhighway becomes damaged, thus disrupting the normal functions of neurons (Tau protein in Alzheimer’s disease).

Researchers from the University of Cambridge have made significant strides in understanding Alzheimer’s disease by using super-resolution microscopy to observe tau protein aggregates within cells with the help of the Cobolt 06-MLD. The group used the following wavelengths: 405, 488, 561 and 638 nm.

For the first time, scientists are able to visualise how tau aggregates form and replicate. Their study highlights that even without external seeding, cells can spontaneously form small tau aggregates.

Significance of the study:

The research is significant as it clarifies how tau aggregates replicate themselves, which helps advance our knowledge on the mechanisms behind neurodegenerative disease such as Alzheimer’s. Researchers will be able to harness this information for early detection and diagnosis to empower earlier treatment and better patient outcomes for the future.

Conformational coupling of the sialic acid TRAP transporter HiSiaQM with its substrate binding protein HiSiaP

Researchers from the University Hospital of Bonn and the University of Bonn in collaboration with the University of York, have uncovered how bacterial proteins work together to transport sialic acid, a crucial nutrient, across cell membranes. The study, published in Nature Communications, focuses on the TRAP (Tripartite ATP-independent Periplasmic)  transporter system, specifically examining the proteins HiSiaQM and HiSiaP. 

In their finding they observed that the TRAP transporter uses a substrate-binding protein (SBP) to capture sialic acid, a sugar molecule. The study identified how certain mutations could trap HiSiaP in a closed state when it binds sialic acid, providing insight into the protein’s shape changes during the transport process.

A notable technique used in the study was disulfide engineering, an important biotechnological tool to study protein dynamics, to “lock” the transporter and SBP in specific states. To visualize the proteins, the scientist used a custom-built, single molecule sensitive, inverted microscope capable of total internal reflection fluorescence (TIRF) microscopy with illumination source provided by our Cobolt 06-MLD 488 nm laser.

Significance of the study:

This research provides detailed insights into how bacterial transport systems work, which is crucial for developing strategies to combat bacterial infections. Understanding how this mechanism work opens up potential avenues for developing new antibiotics that can disrupt this transport system. By inhibiting the TRAP transporter, it might be possible to prevent pathogenic bacteria from acquiring essential nutrients, thereby enhancing the effectiveness of the immune response against these bacteria.

REFERENCES:  ScienceDaily; ​​ Phys.org; ​​ImmunoSensation² ; Disulfide