Tag: biology

Adsorption of SARS-CoV-2 Spike Protein S1 at Oxide Surfaces Studied by High-Speed Atomic Force Microscopy

The ongoing coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) represents a serious threat to the health of millions of people. Respiratory viruses such as SARS-CoV-2 can be transmitted via airborne and fomite routes. The latter requires virion adsorption at abiotic surfaces and most likely involves the SARS-CoV-2 spike protein subunit 1 (S1), which is the outermost point of its envelope. Understanding S1 spike protein interaction with fomite surfaces thus represents an important milestone on the road to fighting the spread of COVID-19.*

In the article “Adsorption of SARS-CoV-2 Spike Protein S1 at Oxide Surfaces Studied by High-Speed Atomic Force Microscopy “ Yang Xin, Guido Grundmeier and Adrian Keller describe how high-speed atomic force microscopy (HS-AFM) is used to monitor the adsorption of the SARS-CoV-2 spike protein S1 at Al2O3(0001) and TiO2(100) surfaces in situ. *

NanoWorld Ultra-Short Cantilevers of the USC-F0.3-k0.3 AFM probe type were used for the high-speed atomic force microscopy. *

Figure 2 from Yang Xin et al Adsorption of SARS-CoV-2 Spike Protein S1 at Oxide Surfaces Studied by High-Speed Atomic Force Microscopy HS-AFM images (1 × 1 μm2) of SARS-CoV-2 spike protein S1 in 10 mM Tris (pH 7.5) adsorbed to a) an Al2O3(0001) and b) a TiO2(100) surface recorded at different time points as indicated. Height scales are 5 nm for the clean substrate surfaces at 0 s and 12 nm for the protein covered surfaces at later time points. Below the HS-AFM images, the corresponding height distribution functions are depicted. The vertical lines in the plots represent the height thresholds applied in the statistical analyses. NanoWorld Ultra-Short Cantilevers of the USC-F0.3-k0.3 AFM probe type were used for the high-speed atomic force microscopy.
Figure 2 from Yang Xin et al Adsorption of SARS-CoV-2 Spike Protein S1 at Oxide Surfaces Studied by High-Speed Atomic Force Microscopy
HS-AFM images (1 × 1 μm2) of SARS-CoV-2 spike protein S1 in 10 mM Tris (pH 7.5) adsorbed to a) an Al2O3(0001) and b) a TiO2(100) surface recorded at different time points as indicated. Height scales are 5 nm for the clean substrate surfaces at 0 s and 12 nm for the protein covered surfaces at later time points. Below the HS-AFM images, the corresponding height distribution functions are depicted. The vertical lines in the plots represent the height thresholds applied in the statistical analyses.

*Yang Xin, Guido Grundmeier, Adrian Keller
Adsorption of SARS-CoV-2 Spike Protein S1 at Oxide Surfaces Studied by High-Speed Atomic Force Microscopy
Advanced NanoBioMed Research, Volume 1, Issue 2, February 2021, 2000024
DOI: https://doi.org/10.1002/anbr.202000024

Open Access : The article “Adsorption of SARS-CoV-2 Spike Protein S1 at Oxide Surfaces Studied by High-Speed Atomic Force Microscopy” by Yang Xin, Guido Grundmeier and Adrian Keller is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/.

Tissue mechanics and expression of TROP2 in oral squamous cell carcinoma with varying differentiation

Atomic Force Microscopy ( AFM ) can be utilized to determine the mechanical properties of tumor tissues in different kinds of cancers, for example breast cancer, liver cancer and lung cancer.

Oral squamous cell carcinoma (OSCC) is a common subtype of head and neck and other malignant tumors that occurs in increasing numbers. It is therefore important to learn more about the biological factors connected with the early diagnosis and treatment of OSCC. *

The human trophoblast cell surface antigen 2 (TROP2), which is also called tumor-associated calcium signal transduction-2 (TACSTD-2), is a surface glycoprotein encoded by TACSTD. *

Among the various biochemical mechanisms involved in tumorigenesis, the role of β-catenin has been studied extensively. This has shed light on the biological functions of TROP2 and its use as a prognostic biomarker for OSCC. *

TROP2 regulates tumorigenic properties including cancer cell adhesion, invasion, and migration and is overexpressed in many human cancers. Inhibiting TROP2 expression has shown promise in clinical applications. *

In the article “Tissue mechanics and expression of TROP2 in oral squamous cell carcinoma with varying differentiation” Baoping Zhang, Shuting Gao, Ruiping Li, Yiting Li, Rui Cao, Jingyang Cheng, Yumeng Guo, Errui Wang, Ying Huang and Kailiang Zhang investigate the role of TROP2 in OSCC patients using a combination of biophysical approaches including atomic force microscopy. *

The authors demonstrate the tissue morphology and mechanics of OSCC samples during tumor development using NanoWorld Pointprobe® CONTR AFM probes for the Atomic Force Microscopy described in the article and they believe that their findings will help develop TROP2 in accurately diagnosing OSCC in tumors with different grades of differentiation. *

Figure 5 from Baoping Zhang et al. “Tissue mechanics and expression of TROP2 in oral squamous cell carcinoma with varying differentiation”: Surface morphology of OSCC tissue sections via AFM detection, irregular morphology appeared in the low differentiation NanoWorld Pointprobe CONTR AFM probes were used for the Atomic Force Microscopy
Figure 5 from Baoping Zhang et al. “Tissue mechanics and expression of TROP2 in oral squamous cell carcinoma with varying differentiation”:
Surface morphology of OSCC tissue sections via AFM detection, irregular morphology appeared in the low differentiation

*Baoping Zhang, Shuting Gao, Ruiping Li, Yiting Li, Rui Cao, Jingyang Cheng, Yumeng Guo, Errui Wang, Ying Huang and Kailiang Zhang
Tissue mechanics and expression of TROP2 in oral squamous cell carcinoma with varying differentiation
BMC Cancer volume 20, Article number: 815 (2020)
DOI: https://doi.org/10.1186/s12885-020-07257-7

Please follow this external link to read the whole article: https://rdcu.be/cfC9G

Open Access : The article “Tissue mechanics and expression of TROP2 in oral squamous cell carcinoma with varying differentiation” by Baoping Zhang, Shuting Gao, Ruiping Li, Yiting Li, Rui Cao, Jingyang Cheng, Yumeng Guo, Errui Wang, Ying Huang and Kailiang Zhang is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/.

Carbon nanotube porin diffusion in mixed composition supported lipid bilayers

Lipid membranes play a key role in living systems by providing a structural barrier that separates cellular compartments. Bilayer fluidity in the lateral plane is a key property of lipid membranes, that allows the membrane to have sufficient flexibility to accommodate dynamic stresses, shape changes and rearrangements accompanying the cellular lifecycle.*

In the article “Carbon nanotube porin diffusion in mixed composition supported lipid bilayers” Kylee Sullivan, Yuliang Zhang, Joseph Lopez, Mary Lowe and Aleksandr Noy describe how they used high-speed atomic force microscopy (HS-AFM) and all-atom molecular dynamics (MD) simulations to study the behavior of CNTPs in a mixed lipid membrane consisting of DOPC lipid with a variable percentage of DMPC lipid added to it. HS-AFM data reveal that the CNTPs undergo diffusive motion in the bilayer plane.*

Motion trajectories extracted from the HS-AFM movies indicate that CNTPs exhibit diffusion coefficient values broadly similar to values reported for membrane proteins in supported lipid bilayers. The data also indicate that increasing the percentage of DMPC leads to a marked slowing of CNTP diffusion. MD simulations reveal a CNTP-lipid assembly that diffuses in the membrane and show trends that are consistent with the experimental observations. *

The above-mentioned study confirms that CNTPs mimic the major features of the diffusive movement of biological pores in lipid membranes and shows how the increase in bilayer viscosity leads to a corresponding slowdown in protein motion. It should be possible to extend this approach to studies of other membrane protein dynamics in supported lipid bilayers. The authors note that those studies, however, will need to be mindful of the challenge of unambiguous visualization of the membrane components, especially in systems that incorporate smaller proteins, such as antimicrobial peptides. Another challenge that could complicate these studies would be microscopic phase separation of the lipid matrix that could lead to complicated pore dynamics in the membrane. *

NanoWorld Ultra-Short AFM cantilevers with high-density carbon/diamond-like carbon (HDC/DLC) AFM tips of the USC-F1.2-k0.15 type were used for the high-speed atomic force microscopy described in the article. *

Figure 2 from “Carbon nanotube porin diffusion in mixed composition supported lipid bilayers” by Kylee Sullivan et al.: CNTP motion in supported lipid bilayers. (a) Representative frames (with times in seconds indicated on each image) from an HS-AFM movie showing a CNTP diffusing in a supported lipid bilayer with 80:20 DOPC-DMPC ratio (see also Supplementary Movie 2). (b) A representative trajectory for CNTP diffusion in the bilayer. The time step between each datapoint is 0.5 s. NanoWorld Ultra-Short AFM Cantilvers USC-F1.2-k0.15 were used for the HS-AFM imaging
Figure 2 a and b from “Carbon nanotube porin diffusion in mixed composition supported lipid bilayers” by Kylee Sullivan et al.:

CNTP motion in supported lipid bilayers. (a) Representative frames (with times in seconds indicated on each image) from an HS-AFM movie showing a CNTP diffusing in a supported lipid bilayer with 80:20 DOPC-DMPC ratio (see also Supplementary Movie 2). (b) A representative trajectory for CNTP diffusion in the bilayer. The time step between each datapoint is 0.5 s.
Please refer to the full article cited below for the full figure.

*Kylee Sullivan, Yuliang Zhang, Joseph Lopez, Mary Lowe and Aleksandr Noy
Carbon nanotube porin diffusion in mixed composition supported lipid bilayers
Nature Scientific Reports volume 10, Article number: 11908 (2020)
DOI: https://doi.org/10.1038/s41598-020-68059-2

Please follow this external link to read the full article: https://rdcu.be/b69wj

Open Access : The article “Carbon nanotube porin diffusion in mixed composition supported lipid bilayers” by Kylee Sullivan, Yuliang Zhang, Joseph Lopez, Mary Lowe and Aleksandr Noy is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit https://creativecommons.org/licenses/by/4.0/.