scholarly journals Chlamydomonas State Transition Is Quiet Around Pyrenoid and Independent from Thylakoid Deformation

2021 ◽  
Author(s):  
Xianjun Zhang ◽  
Yuki Fujita ◽  
Naoya Kaneda ◽  
Ryutaro Tokutsu ◽  
shen Ye ◽  
...  

Photosynthetic organisms have developed a rapid regulation mechanism called state transition (ST) to rapidly adjust the excitation balance between two photosystems by light-harvesting complex II (LHCII) movement. Though many researchers have assumed coupling of the ultrastructural dynamics of the thylakoid membrane to the ST mechanism, how ST is related to the ultrastructural dynamic of the thylakoid in Chlamydomonas remains elusive. To clarify the above-mentioned relation, here we used two specialized microscope techniques, observation via the excitation-spectral microscope (ESM) developed recently by us and the super-resolution imaging based on structured illumination microscopy (SIM). The ESM observation revealed a highly reversible rearrangement of LHCII-related fluorescence. More importantly, it clarified lower ST activity in the region surrounding the pyrenoid, which is the specific subcellular compartment associated with the carbon-fixation reaction. On the other hand, the SIM observation resolved partially irreversible fine thylakoid transformations induced by the ST-inducing illumination. Fine irreversible thylakoid transformation was also observed for the Stt7-kinase-lacking mutant. This result, together with the nearly equal structural changes in the less active ST regions around the pyrenoid, suggested the independence of the observed fine structural changes from the LHCII phosphorylation.

2016 ◽  
Author(s):  
Matthew J. Niederhuber ◽  
Talley J. Lambert ◽  
Clarence Yapp ◽  
Pamela A. Silver ◽  
Jessica K. Polka

AbstractCarbon fixation in cyanobacteria makes a major contribution to the global carbon cycle. The cyanobacterial carboxysome is a proteinaceous microcompartment that protects and concentrates the carbon-fixing enzyme RuBisCO in a paracrystalline lattice, making it possible for these organisms to fix CO2 from the atmosphere. The protein responsible for the organization of this lattice in beta-type carboxysomes of the freshwater cyanobacterium Synechococcus elongatus, CcmM, occurs in two isoforms thought to localize differentially within the carboxysome matrix. Here we use widefield timelapse and 3D-structured illumination microscopy (3D-SIM) to study the recruitment and localization of these two isoforms. We demonstrate that this super-resolution technique is capable of successfully resolving the outer protein shell of the carboxysome from its internal cargo. We develop an automated analysis pipeline to analyze and quantify 3D-SIM images and generate a population level description of carboxysome shell protein, RuBisCO, and CcmM isoform localization. We find that both CcmM isoforms colocalize in space and time, prompting a revised model of the internal arrangement of the beta carboxysome.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Liliana Barbieri ◽  
Huw Colin-York ◽  
Kseniya Korobchevskaya ◽  
Di Li ◽  
Deanna L. Wolfson ◽  
...  

AbstractQuantifying small, rapidly evolving forces generated by cells is a major challenge for the understanding of biomechanics and mechanobiology in health and disease. Traction force microscopy remains one of the most broadly applied force probing technologies but typically restricts itself to slow events over seconds and micron-scale displacements. Here, we improve >2-fold spatially and >10-fold temporally the resolution of planar cellular force probing compared to its related conventional modalities by combining fast two-dimensional total internal reflection fluorescence super-resolution structured illumination microscopy and traction force microscopy. This live-cell 2D TIRF-SIM-TFM methodology offers a combination of spatio-temporal resolution enhancement relevant to forces on the nano- and sub-second scales, opening up new aspects of mechanobiology to analysis.


Nanophotonics ◽  
2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ruslan Röhrich ◽  
A. Femius Koenderink

AbstractStructured illumination microscopy (SIM) is a well-established fluorescence imaging technique, which can increase spatial resolution by up to a factor of two. This article reports on a new way to extend the capabilities of structured illumination microscopy, by combining ideas from the fields of illumination engineering and nanophotonics. In this technique, plasmonic arrays of hexagonal symmetry are illuminated by two obliquely incident beams originating from a single laser. The resulting interference between the light grating and plasmonic grating creates a wide range of spatial frequencies above the microscope passband, while still preserving the spatial frequencies of regular SIM. To systematically investigate this technique and to contrast it with regular SIM and localized plasmon SIM, we implement a rigorous simulation procedure, which simulates the near-field illumination of the plasmonic grating and uses it in the subsequent forward imaging model. The inverse problem, of obtaining a super-resolution (SR) image from multiple low-resolution images, is solved using a numerical reconstruction algorithm while the obtained resolution is quantitatively assessed. The results point at the possibility of resolution enhancements beyond regular SIM, which rapidly vanishes with the height above the grating. In an initial experimental realization, the existence of the expected spatial frequencies is shown and the performance of compatible reconstruction approaches is compared. Finally, we discuss the obstacles of experimental implementations that would need to be overcome for artifact-free SR imaging.


2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Gang Wen ◽  
Simin Li ◽  
Linbo Wang ◽  
Xiaohu Chen ◽  
Zhenglong Sun ◽  
...  

AbstractStructured illumination microscopy (SIM) has become a widely used tool for insight into biomedical challenges due to its rapid, long-term, and super-resolution (SR) imaging. However, artifacts that often appear in SIM images have long brought into question its fidelity, and might cause misinterpretation of biological structures. We present HiFi-SIM, a high-fidelity SIM reconstruction algorithm, by engineering the effective point spread function (PSF) into an ideal form. HiFi-SIM can effectively reduce commonly seen artifacts without loss of fine structures and improve the axial sectioning for samples with strong background. In particular, HiFi-SIM is not sensitive to the commonly used PSF and reconstruction parameters; hence, it lowers the requirements for dedicated PSF calibration and complicated parameter adjustment, thus promoting SIM as a daily imaging tool.


Author(s):  
Yizhao Guan ◽  
Hiromasa Kume ◽  
Shotaro Kadoya ◽  
Masaki Michihata ◽  
Satoru Takahashi

Abstract Microstructures are widely used in the manufacture of functional surfaces. An optical-based super-resolution, non-invasive method is preferred for the inspection of surfaces with massive microstructures. The Structured Illumination Microscopy (SIM) uses standing-wave illumination to reach optical super-resolution. Recently, coherent SIM is being studied. It can obtain not only the super-resolved intensity distribution but also the phase and amplitude distribution of the sample surface beyond the diffraction limit. By analysis of the phase-depth dependency, the depth measurement for microgroove structures with coherent SIM is expected. FDTD analysis is applied for observing the near-field response of microgroove under the standing-wave illumination. The near-field phase shows depth dependency in this analysis. Moreover, the effects from microgroove width, the incident angle, and the relative position between the standing-wave peak and center of the microgroove are investigated. It is found the near-field phase change can measure depth until 200 nm (aspect ratio 1) with an error of up to 20.4 nm in the case that the microgroove width is smaller than half of the wavelength.


2020 ◽  
Vol 52 (1) ◽  
pp. 369-393
Author(s):  
Minami Yoda

Quantifying submillimeter flows using optical diagnostic techniques is often limited by a lack of spatial resolution and optical access. This review discusses two super-resolution imaging techniques, structured illumination microscopy and total internal reflection fluorescence or microscopy, which can visualize bulk and interfacial flows, respectively, at spatial resolutions below the classic diffraction limits. First, we discuss the theory and applications of structured illumination for optical sectioning, i.e., imaging a thin slice of a flow illuminated over its entire volume. Structured illumination can be used to visualize the interior of multiphase flows such as sprays by greatly reducing secondary scattering. Second, the theory underlying evanescent waves is introduced, followed by a review of how total internal reflection microscopy has been used to visualize interfacial flows over the last 15 years. Both techniques, which are starting to be used in fluid mechanics, could significantly improve quantitative imaging of microscale and macroscale flows.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Karl Zhanghao ◽  
Xingye Chen ◽  
Wenhui Liu ◽  
Meiqi Li ◽  
Yiqiong Liu ◽  
...  

Abstract Fluorescence polarization microscopy images both the intensity and orientation of fluorescent dipoles and plays a vital role in studying molecular structures and dynamics of bio-complexes. However, current techniques remain difficult to resolve the dipole assemblies on subcellular structures and their dynamics in living cells at super-resolution level. Here we report polarized structured illumination microscopy (pSIM), which achieves super-resolution imaging of dipoles by interpreting the dipoles in spatio-angular hyperspace. We demonstrate the application of pSIM on a series of biological filamentous systems, such as cytoskeleton networks and λ-DNA, and report the dynamics of short actin sliding across a myosin-coated surface. Further, pSIM reveals the side-by-side organization of the actin ring structures in the membrane-associated periodic skeleton of hippocampal neurons and images the dipole dynamics of green fluorescent protein-labeled microtubules in live U2OS cells. pSIM applies directly to a large variety of commercial and home-built SIM systems with various imaging modality.


2021 ◽  
Author(s):  
Anna Loeschberger ◽  
Yauheni Novikau ◽  
Ralf Netz ◽  
Marie-Christin Spindler ◽  
Ricardo Benavente ◽  
...  

Three-dimensional (3D) multicolor super-resolution imaging in the 50-100 nm range in fixed and living cells remains challenging. We extend the resolution of structured illumination microscopy (SIM) by an improved nonlinear iterative reconstruction algorithm that enables 3D multicolor imaging with improved spatiotemporal resolution at low illumination intensities. We demonstrate the performance of dual iterative SIM (diSIM) imaging cellular structures in fixed cells including synaptonemal complexes, clathrin coated pits and the actin cytoskeleton with lateral resolutions of 60-100 nm with standard fluorophores. Furthermore, we visualize dendritic spines in 70 micrometer thick brain slices with an axial resolution < 200 nm. Finally, we image dynamics of the endoplasmatic reticulum and microtubules in living cells with up to 255 frames/s.


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