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1.
Heliyon ; 9(2): e13171, 2023 Feb.
Article in English | MEDLINE | ID: mdl-36755605

ABSTRACT

Hematoxylin and eosin (H&E) staining is the gold standard for tissue characterization in routine pathological diagnoses. However, these visible light dyes do not exclusively label the nuclei and cytoplasm, making clear-cut segmentation of staining signals challenging. Currently, fluorescent staining technology is much more common in clinical research for analyzing tissue morphology and protein distribution owing to its advantages of channel independence, multiplex labeling, and the possibility of enabling 3D tissue labeling. Although both H&E and fluorescent dyes can stain the nucleus and cytoplasm for representative tissue morphology, color variation between these two staining technologies makes cross-analysis difficult, especially with computer-assisted artificial intelligence (AI) algorithms. In this study, we applied color normalization and nucleus extraction methods to overcome the variation between staining technologies. We also developed an available workflow for using an H&E-stained segmentation AI model in the analysis of fluorescent nucleic acid staining images in breast cancer tumor recognition, resulting in 89.6% and 80.5% accuracy in recognizing specific tumor features in H&E- and fluorescent-stained pathological images, respectively. The results show that the cross-staining inference maintained the same precision level as the proposed workflow, providing an opportunity for an expansion of the application of current pathology AI models.

2.
J Histochem Cytochem ; 70(8): 597-608, 2022 08.
Article in English | MEDLINE | ID: mdl-35912522

ABSTRACT

Microscopic examination of biopsied and resected prostatic specimens is the mainstay in the diagnosis of prostate cancer. However, conventional analysis of hematoxylin and eosin (H&E)-stained tissue is time-consuming and offers limited two-dimensional (2D) information. In the current study, we devised a method-termed Prostate Rapid Optical examination for cancer STATus (proSTAT)-for rapid screening of prostate cancer using high-resolution 2D and three-dimensional (3D) confocal images obtained after hydrophilic tissue clearing of 100-µm-thick tissue slices. The results of the proSTAT method were compared with those of traditional H&E stains for the analysis of cores (n=15) obtained from radical prostatectomy specimens (n=5). Gland lumen formation, consistent with Gleason pattern 3, was evident following tracking of multiple optical imaging sections. In addition, 3D rendering allowed visualizing a tubular network of interconnecting branches. Rapid 3D fluorescent labeling of tumor protein p63 accurately distinguished prostate adenocarcinoma from normal tissue and benign lesions. Compared with conventional stains, the 3D spatial and molecular information extracted from proSTAT may significantly increase the amount of available data for pathological assessment of prostate specimens. Our approach is amenable to automation and-subject to independent validation-can find a wide spectrum of clinical and research applications.


Subject(s)
Prostate , Prostatic Neoplasms , Coloring Agents , Humans , Male , Microscopy, Confocal , Neoplasm Grading , Prostate/diagnostic imaging , Prostate/pathology , Prostatectomy/methods , Prostatic Neoplasms/diagnostic imaging , Prostatic Neoplasms/pathology
3.
Recent Pat Nanotechnol ; 12(3): 218-230, 2018.
Article in English | MEDLINE | ID: mdl-30117404

ABSTRACT

BACKGROUND: The TPP technology is a "nano-optics" 3D printing technology that develops in recent years. Compared with the traditional 3D printing technology, the TPP-3DP technique that takes near-infrared light femtosecond pulse laser as the light source can break through the limitation of optical diffraction and manufacture nanoscale 3D structures in arbitrary shapes with high resolution. METHOD: The research develops a claim-based patent analysis method to identify technical features via the analysis of claim, especially the analysis of plural elements of independent claim. Furthermore, we analyze the subject matters and technical features of claims through claim-base analytical method to observe the patent trend of competitors and understand the current situation of competitors' technical distribution in related industries, in order to provide useful information for enterprises to determine R&D strategies. RESULTS: The result shows 3M Company possesses numerous patent portfolios that base on the diversified innovative applications of TPP technology. Nanoscribe Company has a long-term advantage in monopolizing this technology. The patents in TPP-3DP field can be grouped into five categories relating to application, including micro-optics device, photonic crystal, biomedical, microfluidics and MEMS. CONCLUSION: The findings of this review confirm the TPP-based 3D printing (TPP-3DP) technology has broad application prospects, of which the hydrogel material applied in tissue engineering and drug delivery is the future trend. Highly-initiated water-soluble initiators are particularly needed to increase its resolution and will be the direction of emerging technology in this domain.

4.
Recent Pat Nanotechnol ; 12(3): 231-242, 2018.
Article in English | MEDLINE | ID: mdl-30081794

ABSTRACT

BACKGROUND: Because line width has been close to atom size, for semiconductor industry, except for achieving the target of line width, the cost will be more important. The mask-less laser interference lithography (LIL) technique lowers the cost makes it standing out in the market of lithographic equipment of the excessive cost in the semiconductor industry. METHOD: The Keywords of patent retrieval with the theme of LIL are based on the technical features of both the conditions of producing interference lithography and different types of experimental configuration of LIL. Method of patent retrieval include Boolean logic operators are used to express the relationship between sets. Furthermore, it's necessary to find whether common patent classification codes exist in the highly correlated patents and confirm the definition of that. RESULTS: The patent review in this research show the patents of LIL technique are classified according to optical method and lithographic equipment. The patents related to optical method of LIL technique take beam splitter based configuration as the main stream; in the technique of lithographic equipment, the patents of system planning technique are the most. CONCLUSION: The findings of this review confirm the importance of improving the precision of LIL technique for avoiding the defocus of high-density line width. Besides, it's particularly suitable for the micro nanofluid device in the emerging bionanotechnology to observe fluid behavior at the minimum scale. It doesn't need mask and can produce periodic pattern with nanoscale make it devote to the field of periodicity.

5.
Nanoscale ; 10(13): 6214, 2018 Mar 29.
Article in English | MEDLINE | ID: mdl-29595205

ABSTRACT

Correction for 'A high quality liquid-type quantum dot white light-emitting diode' by Chin-Wei Sher et al., Nanoscale, 2016, 8, 1117-1122.

6.
Nanotechnology ; 28(47): 475301, 2017 Nov 24.
Article in English | MEDLINE | ID: mdl-28936985

ABSTRACT

The periodic structure of laser interference lithography (LIL) fabrication is superior to other lithography technologies. In contrast to traditional lithography, LIL has the advantages of being a simple optical system with no mask requirements, low cost, high depth of focus, and large patterning area in a single exposure. Generally, a simulation pattern for the periodic structure is obtained through optical interference prior to its fabrication through LIL. However, the LIL process is complex and combines the fields of optical and polymer materials; thus, a single simulation theory cannot reflect the real situation. Therefore, this research integrates multiple theories, including those of optical interference, standing waves, and photoresist characteristics, to create a mathematical model for the LIL process. The mathematical model can accurately estimate the exposure time and reduce the LIL process duration through trial and error.

7.
Anal Biochem ; 539: 11-21, 2017 12 15.
Article in English | MEDLINE | ID: mdl-28942943

ABSTRACT

We report here the development of a compartmentalized culture device that allows the spatial separation of the somatodendrites and axons of central nervous system (CNS) neurons. The device consists of two compartments separated by a septum constructed by attaching a porous polycarbonate track etch (PCTE) filter on top of a microchannel-filled polydimethylsiloxane (PDMS) membrane. The surface and microchannels of the septum are coated and filled, respectively, with materials that support neuron growth and neurite migration. When rat hippocampal neurons are cultured in the top compartment, axons are the only processes that can migrate through the septum to the bottom compartment. The axons in the bottom compartment can be studied directly in real-time or through immunofluorescence staining after fixation. Axons containing ∼3 µg protein can be isolated from each device for biochemical analyses. In addition, the septum also impedes the movement of small molecules between the top and bottom compartments. This feature allows the somatodendrites and axons of neurons, which occupy the top and bottom compartments of the device, respectively, to be manipulated independently. The potential applications of the device as a tool in diverse studies concerning neuronal axons and in screening reagents that regulate axonal functions have also been discussed.


Subject(s)
Axons/metabolism , Cell Culture Techniques/instrumentation , Cell Culture Techniques/methods , Neurons/cytology , Animals , Axons/drug effects , Cells, Cultured , Dendrites/drug effects , Dendrites/physiology , Dimethylpolysiloxanes/chemistry , Embryo, Mammalian/cytology , Glutamic Acid/toxicity , Microfluidic Analytical Techniques/instrumentation , Microscopy, Fluorescence , Microtubules/physiology , Neurons/metabolism , Paclitaxel/pharmacology , Rats
8.
J Synchrotron Radiat ; 23(Pt 3): 658-64, 2016 05.
Article in English | MEDLINE | ID: mdl-27140144

ABSTRACT

Hard X-ray Fabry-Perot resonators (FPRs) made from sapphire crystals were constructed and characterized. The FPRs consisted of two crystal plates, part of a monolithic crystal structure of Al2O3, acting as a pair of mirrors, for the backward reflection (0 0 0 30) of hard X-rays at 14.3147 keV. The dimensional accuracy during manufacturing and the defect density in the crystal in relation to the resonance efficiency of sapphire FPRs were analyzed from a theoretical standpoint based on X-ray cavity resonance and measurements using scanning electron microscopic and X-ray topographic techniques for crystal defects. Well defined resonance spectra of sapphire FPRs were successfully obtained, and were comparable with the theoretical predictions.

9.
Nanoscale ; 8(2): 1117-22, 2016 Jan 14.
Article in English | MEDLINE | ID: mdl-26666455

ABSTRACT

This study demonstrates a novel package design to store colloidal quantum dots in liquid format and integrate them with a standard LED. The high efficiency and high quality color performance at a neutral white correlated color temperature is demonstrated. The experimental results indicate that the liquid-type quantum dot white light-emitting diode (LQD WLED) is highly efficient and reliable. The luminous efficiency and color rendering index (CRI) of the LQD WLED can reach 271 lm Wop(-1) and 95, respectively. Moreover, a glass box is employed to prevent humidity and oxygen erosion. With this encapsulation design, our quantum dot box can survive over 1000 hours of storage time.

10.
Opt Express ; 23(19): A1167-78, 2015 Sep 21.
Article in English | MEDLINE | ID: mdl-26406747

ABSTRACT

This study demonstrates the flexible white LED structure with high lumen efficiency and uniform optical performance for neutral white and warm white CCT. Flip-chip LEDs were attached on a polyimide substrate with copper strips as electrical and thermal conduction paths. Yellow phosphors are mixed with polydimenthysiloxane (PDMS) to provide mechanical support and flexibility. The light efficiency of this device can reach 120 lm/W and 85% of light output uniformity of the emission area can be achieved. Moreover, the optical simulation is employed to evaluate various designs of this flexible film in order to obtain uniform output. Both the pitch between the individual devices and the thickness of the phosphor film are calculated for optimization purpose. This flexible white LED with high lumen efficiency and good reliability is suitable for the large area fixture in the general lighting applications.

11.
Nat Commun ; 6: 7775, 2015 Jul 16.
Article in English | MEDLINE | ID: mdl-26178754

ABSTRACT

The detection of environmental temperature and regulation of body temperature are integral determinants of behaviour for all animals. These functions become less efficient in aged animals, particularly during exposure to cold environments, yet the cellular and molecular mechanisms are not well understood. Here, we identify an age-related change in the temperature preference of adult fruit flies that results from a shift in the relative contributions of two parallel mushroom body (MB) circuits­the ß'- and ß-systems. The ß'-circuit primarily controls cold avoidance through dopamine signalling in young flies, whereas the ß-circuit increasingly contributes to cold avoidance as adult flies age. Elevating dopamine levels in ß'-afferent neurons of aged flies restores cold sensitivity, suggesting that the alteration of cold avoidance behaviour with ageing is functionally reversible. These results provide a framework for investigating how molecules and individual neural circuits modulate homeostatic alterations during the course of senescence.


Subject(s)
Aging/physiology , Behavior, Animal/physiology , Body Temperature Regulation/physiology , Choice Behavior/physiology , Dopamine/metabolism , Mushroom Bodies/metabolism , Neurons/metabolism , Receptors, Dopamine/metabolism , Temperature , Animals , Avoidance Learning/physiology , Calcium/metabolism , Cold Temperature , Drosophila melanogaster , Mushroom Bodies/cytology
12.
Biomed Opt Express ; 6(2): 514-23, 2015 Feb 01.
Article in English | MEDLINE | ID: mdl-25780741

ABSTRACT

We developed a real-time automated laser-tracking system combined with continuous wave 1064-nm infrared or 473-nm blue lasers to provide punishment for studying memory in Drosophila Melanogaster. Combining optogenetic tools with laser properties, such as 473-nm and 593-nm lasers that activate light sensitive proteins in artificial transgenic flies, we can manipulate the specific neuron of an assigned fly among multiple flies to investigate neuron circuit relationships in social interactions. In restraining condition assay or optogenetic experiments, a ventral irradiated system would be more efficient due to higher ventral cuticle transmissions and neuron ganglia locations. Therefore, ventral irradiated systems cause less perturbation during behavior studies.

13.
Langmuir ; 30(36): 10940-9, 2014 Sep 16.
Article in English | MEDLINE | ID: mdl-25149642

ABSTRACT

The formation of hierarchical architectures is of fundamental importance and yet a relatively elusive problem concerning many natural and industrial processes. In this paper, a nanopost array platform, or a nanopost substrate, has been developed to address this issue through a model study of the drying structures of phosphate buffered saline (PBS) solution. Unlike on a plain surface, highly ramified salt structures are formed by simply allowing the nanopost substrate wetted with the salt solution to dry, a process that completes within minutes at room temperature. The branches of salt structures have similar shapes repeating at different length scales, ranging from ∼200 nm up to a few centimeters in length, covering a 2 × 2 cm(2) area patterned with nanoposts fabricated in photoresist via laser interference lithography (LIL). Scanning electromicrograph (SEM) images show that salt structures are formed around nanoposts, and characteristic features of these salt structures can be modulated and predicted based on the surface properties and geometrical arrangements of nanoposts, suggesting that nanoposts can be used to guide the organization and crystallization of salts. This nanopost-guided crystallization approach is robust, rapid, versatile, and amenable to real-time observation and mass production, providing a great opportunity for the study and creation of large-scale hierarchical structures.


Subject(s)
Nanostructures/chemistry , Phosphates/chemistry , Salts/chemistry , Sodium Chloride/chemistry , Molecular Structure , Particle Size , Surface Properties
14.
Proc Natl Acad Sci U S A ; 111(14): 5367-72, 2014 Apr 08.
Article in English | MEDLINE | ID: mdl-24706830

ABSTRACT

We present an automated laser tracking and optogenetic manipulation system (ALTOMS) for studying social memory in fruit flies (Drosophila melanogaster). ALTOMS comprises an intelligent central control module for high-speed fly behavior analysis and feedback laser scanning (∼40 frames per second) for targeting two lasers (a 473-nm blue laser and a 593.5-nm yellow laser) independently on any specified body parts of two freely moving Drosophila adults. By using ALTOMS to monitor and compute the locations, orientations, wing postures, and relative distance between two flies in real time and using high-intensity laser irradiation as an aversive stimulus, this laser tracking system can be used for an operant conditioning assay in which a courting male quickly learns and forms a long-lasting memory to stay away from a freely moving virgin female. With the equipped lasers, channelrhodopsin-2 and/or halorhodopsin expressed in selected neurons can be triggered on the basis of interactive behaviors between two flies. Given its capacity for optogenetic manipulation to transiently and independently activate/inactivate selective neurons, ALTOMS offers opportunities to systematically map brain circuits that orchestrate specific Drosophila behaviors.


Subject(s)
Drosophila melanogaster/physiology , Neurons/physiology , Optogenetics , Animals , Behavior, Animal , Conditioning, Classical , Female , Male , Memory
15.
Nanotechnology ; 24(45): 455301, 2013 Nov 15.
Article in English | MEDLINE | ID: mdl-24141145

ABSTRACT

The non-uniform intensity profile of Gaussian-like laser beams used in interference lithography (IL) leads to a non-uniform dose and feature size distribution across the sample. Previously described methods to improve dose uniformity are reviewed. However, here we examine the behavior of the non-uniformity from the viewpoint of photoresist response rather than the IL system configuration. Samples with a fixed intra-sample dose profile were exposed with an increasing average dose. A line/space pattern with a period of 240 nm across an area of 2 × 2 cm(2) was produced using IL on identical samples using a HeCd laser operated at 325 nm and a Lloyd's mirror IL system. A binary model of photoresist response predicts that the absolute range of line widths in nanometers should be significantly reduced as the overall sample dose is increased. We have experimentally verified a reduction in the range of line widths within a given sample from 50 to 16 nm as the overall dose is increased by only 60%. This resulted in a drop in the narrowest line width from 120 to 65 nm. An etch process is demonstrated to increase the line width by generating a wider secondary chrome hard mask from the narrowly patterned primary chrome hard mask. The subsequent fabrication of a silicon nanoimprint mold is used as a demonstration of the technique.

16.
Biomaterials ; 33(20): 5156-65, 2012 Jul.
Article in English | MEDLINE | ID: mdl-22484044

ABSTRACT

This work presents an approach to codelivering transdermally two model drugs, Alexa 488 and Cy5, in sequence, based on a system of polyvinylpyrrolidone microneedles (PVP MNs) that contain pH-responsive poly(d,l-lactic-co-glycolic acid) hollow microspheres (PLGA HMs). The MN system provides the green fluorescence of Alexa 488 in PVP MNs, the red fluorescence of the DiI-labeled PLGA shell of HMs, and the cyan fluorescence of Cy5 in their aqueous core. Combined together, the prepared MN arrays support the localization of the HMs and the monitoring of the release profiles of model drugs within the skin tissues. The key component of this system is NaHCO(3), which can be easily incorporated into HMs. After HMs are treated with an acidic solution (simulating the skin pH environment), protons (H(+)) can rapidly diffuse through the free volume in the PLGA shells to react with NaHCO(3) and form a large number of CO(2) bubbles. This effect generates pressure inside the HMs and creates pores inside their PLGA shells, releasing the encapsulated Cy5. Test MNs were strong enough to be inserted into rat skin without breaking. The PVP MNs were significantly dissolved within minutes, and the first model drug Alexa 488, together with HMs, were successfully deposited into the tissues. Once in the acidic environment of the skin, the released HMs started to release Cy5 and continued to spread throughout the neighboring tissues, in a second step of the release of the drug. This approach can be used clinically to codeliver sequentially and transcutaneously a broad range of drugs.


Subject(s)
Lactic Acid/chemistry , Microspheres , Needles , Polyglycolic Acid/chemistry , Animals , Dimethylpolysiloxanes , Hydrogen-Ion Concentration , Microscopy, Electron, Scanning , Microscopy, Fluorescence , Polylactic Acid-Polyglycolic Acid Copolymer , Rats , Sodium Bicarbonate/chemistry
17.
Langmuir ; 27(19): 11930-42, 2011 Oct 04.
Article in English | MEDLINE | ID: mdl-21859109

ABSTRACT

We study the indentation of a free-standing lipid membrane suspended over a nanopore on a hydrophobic substrate by means of molecular dynamics simulations. We find that in the course of indentation the membrane bends at the point of contact and the fringes of the membrane glide downward intermittently along the pore edges and stop gliding when the fringes reach the edge bottoms. The bending continues afterward, and the large strain eventually induces a phase transition in the membrane, transformed from a bilayered structure to an interdigitated structure. The membrane is finally ruptured when the indentation goes deep enough. Several local physical quantities in the pore regions are calculated, which include the tilt angle of lipid molecules, the nematic order, the included angle, and the distance between neighboring lipids. The variations of these quantities reveal many detailed, not-yet-specified local structural transitions of lipid molecules under indentation. The force-indentation curve is also studied and discussed. The results make a connection between the microscopic structure and the macroscopic properties and provide deep insight into the understanding of the stability of a lipid membrane spanning over nanopore.


Subject(s)
Membranes, Artificial , Molecular Dynamics Simulation , Nanopores , Hydrophobic and Hydrophilic Interactions
18.
Biochemistry ; 49(26): 5408-17, 2010 Jul 06.
Article in English | MEDLINE | ID: mdl-20513152

ABSTRACT

Leptopirosis is a renal disease caused by pathogenic Leptospira that primarily infects the renal proximal tubules, consequently resulting in severe tubular injuries and malfunctions. The protein extracted from the outer membrane of this pathogenic strain contains a major component of a 32 kDa lipoprotein (LipL32), which is absent in the counter membrane of nonpathogenic strains and has been identified as a crucial factor for host cell infection. Previous studies showed that LipL32 induced inflammatory responses and interacted with the extracellular matrix (ECM) of the host cell. However, the exact relationship between LipL32-mediated inflammatory responses and ECM binding is still unknown. In this study, an atomic force microscope with its tip modified by purified LipL32 was used to assess the interaction between LipL32 and cell surface receptors. Furthermore, an antibody neutralization technique was employed to identify Toll-like receptor 2 (TLR2) but not TLR4 as the major target of LipL32 attack. The interaction force between LipL32 and TLR2 was measured as approximately 59.5 +/- 8.7 pN, concurring with the theoretical value for a single-pair molecular interaction. Moreover, transformation of a TLR deficient cell line with human TLR2 brought the interaction force from the basal level to approximately 60.4 +/- 11.5 pN, confirming unambiguously TLR2 as counter receptor for LipL32. The stimulation of CXCL8/IL-8 expression by full-length LipL32 as compared to that without the N-terminal signal peptide domain suggests a significant role of the signal peptide of the protein in the inflammatory responses. This study provides direct evidence that LipL32 binds to TLR2, but not TLR4, on the cell surface, and a possible mechanism for the virulence of leptospirosis is accordingly proposed.


Subject(s)
Bacterial Outer Membrane Proteins/metabolism , Kidney/microbiology , Leptospira/pathogenicity , Lipoproteins/metabolism , Toll-Like Receptor 2/metabolism , Bacterial Outer Membrane Proteins/chemistry , Humans , Inflammation , Kidney/pathology , Leptospira/chemistry , Leptospira/metabolism , Leptospirosis/etiology , Leptospirosis/microbiology , Lipoproteins/chemistry , Microscopy, Atomic Force/methods , Protein Binding , Protein Sorting Signals , Toll-Like Receptor 4 , Virulence
19.
J Biol Chem ; 285(31): 23655-64, 2010 Jul 30.
Article in English | MEDLINE | ID: mdl-20511234

ABSTRACT

Homodimeric H(+)-pyrophosphatase (H(+)-PPase; EC 3.6.1.1) is a unique enzyme playing a pivotal physiological role in pH homeostasis of organisms. This novel H(+)-PPase supplies energy at the expense of hydrolyzing metabolic byproduct, pyrophosphate (PP(i)), for H(+) translocation across membrane. The functional unit for the translocation is considered to be a homodimer. Its putative active site on each subunit consists of PP(i) binding motif, Acidic I and II motifs, and several essential residues. In this investigation structural mapping of these vital regions was primarily determined utilizing single molecule fluorescence resonance energy transfer. Distances between two C termini and also two N termini on homodimeric subunits of H(+)-PPase are 49.3 + or - 4.0 and 67.2 + or - 5.7 A, respectively. Furthermore, putative PP(i) binding motifs on individual subunits are found to be relatively far away from each other (70.8 + or - 4.8 A), whereas binding of potassium and substrate analogue led them to closer proximity. Moreover, substrate analogue but not potassium elicits significant distance variations between two Acidic I motifs and two His-622 residues on homodimeric subunits. Taken together, this study provides the first quantitative measurements of distances between various essential motifs, residues, and putative active sites on homodimeric subunits of H(+)-PPase. A working model is accordingly proposed elucidating the distance variations of dimeric H(+)-PPase upon substrate binding.


Subject(s)
Fluorescence Resonance Energy Transfer/methods , Inorganic Pyrophosphatase/chemistry , Inorganic Pyrophosphatase/physiology , Pyrophosphatases/chemistry , Amino Acid Motifs , Catalytic Domain , Clostridium tetani/enzymology , Dimerization , Escherichia coli/enzymology , Ligands , Microsomes/metabolism , Mutation , Protein Sorting Signals , Protein Transport , Spectrometry, Fluorescence
20.
FEBS J ; 276(16): 4381-94, 2009 Aug.
Article in English | MEDLINE | ID: mdl-19614743

ABSTRACT

Vacuolar H(+)-translocating inorganic pyrophosphatase [vacuolar H(+)-pyrophosphatase (V-PPase); EC 3.6.1.1] is a homodimeric proton translocase; it plays a pivotal role in electrogenic translocation of protons from the cytosol to the vacuolar lumen, at the expense of PP(i) hydrolysis, for the storage of ions, sugars, and other metabolites. Dimerization of V-PPase is necessary for full proton translocation function, although the structural details of V-PPase within the vacuolar membrane remain uncertain. The C-terminus presumably plays a crucial role in sustaining enzymatic and proton-translocating reactions. We used atomic force microscopy to visualize V-PPases embedded in an artificial lipid bilayer under physiological conditions. V-PPases were randomly distributed in reconstituted lipid bilayers; approximately 43.3% of the V-PPase protrusions faced the cytosol, and 56.7% faced the vacuolar lumen. The mean height and width of the cytosolic V-PPase protrusions were 2.8 +/- 0.3 nm and 26.3 +/- 4.7 nm, whereas those of the luminal protrusions were 1.2 +/- 0.1 nm and 21.7 +/- 3.6 nm, respectively. Moreover, both C-termini of dimeric subunits of V-PPase are on the same side of the membrane, and they are close to each other, as visualized with antibody and gold nanoparticles against 6xHis tags on C-terminal ends of the enzyme. The distance between the V-PPase C-terminal ends was determined to be approximately 2.2 +/- 1.4 nm. Thus, our study is the first to provide structural details of a membrane-bound V-PPase dimer, revealing its adjacent C-termini.


Subject(s)
Inorganic Pyrophosphatase/chemistry , Metal Nanoparticles , Microscopy, Atomic Force/methods , Plant Proteins/chemistry , Protein Structure, Quaternary , Antibodies , Gold , Lipid Bilayers , Protein Conformation , Vacuoles/enzymology
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