scholarly journals Nanopore formation in the cuticle of an insect olfactory sensillum

2018 ◽  
Author(s):  
Toshiya Ando ◽  
Sayaka Sekine ◽  
Sachi Inagaki ◽  
Kazuyo Misaki ◽  
Laurent Badel ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Surface Structures ◽  
Biological Functions ◽  
Olfactory Sensilla ◽  
Structural Coloration ◽  
Essential Requirement ◽  
Nano Fabrication ◽  
Cellular Processes ◽  
Nano Structures ◽  
Envelope Layer

SummaryNanometer-level patterned surface structures form the basis of biological functions including superhydrophobicity, structural coloration, and light absorption [1-3]. In insects, the cuticle overlying the olfactory sensilla has multiple small (50–200-nm diameter) pores [4-8], which are supposed to function as a filter that admits odorant molecules, while preventing the entry of larger airborne particles and limiting water loss. However, the cellular processes underlying the patterning of extracellular matrices into functional nano-structures remain unknown. Here we show that cuticular nanopores in Drosophila olfactory sensilla originate from a curved ultrathin film that is formed in the outermost envelope layer of the cuticle, and secreted from specialized protrusions in the plasma membrane of the hair forming (trichogen) cell. The envelope curvature coincides with plasma membrane undulations associated with endocytic structures. The gore-tex/Osiris23 gene encodes an endosomal protein that is essential for envelope curvature, nanopore formation, and odor receptivity, and is expressed specifically in developing olfactory trichogen cells. The 24-member Osiris gene family is expressed in cuticle-secreting cells, and is found only in insect genomes. These results reveal an essential requirement for nanopores for odor reception and identify Osiris genes as a platform for investigating the evolution of surface nano-fabrication in insects.

vitreal cells and specialized phagocytes in the chick embryo retina: A TEM and SEM study

1990 ◽  
Vol 48 (3) ◽  
pp. 330-331
Author(s):  
M.A. Cuadros ◽  
M.J. Martinez-Guerrero ◽  
A. Rios
Keyword(s):  
Cell Death ◽  
Plasma Membrane ◽  
Acid Phosphatase ◽  
Chick Embryo ◽  
Basement Membrane ◽  
Sem Images ◽  
Intimate Contact ◽  
Cellular Processes ◽  
Sem Study ◽  
Free Cells

In the chick embryo retina (days 3-4 of incubation), coinciding with an increase in cell death, specialized phagocytes characterized by intense acid phosphatase activity have been described. In these preparations, all free cells in the vitreal humor (vitreal cells) were strongly labeled. Conventional TEM and SEM techniques were used to characterize them and attempt to determine their relationship with retinal phagocytes.Two types of vitreal cells were distinguished. The first are located at some distance from the basement membrane of the neuroepithelium, and are rounded, with numerous vacuoles and thin cytoplasmic prolongations. Images of exo- and or endocytosis were frequent; the cells showed a well-developed Golgi apparatus (Fig. 1) In SEM images, the cells was covered with short cellular processes (Fig. 3). Cells lying parallel to or alongside the basement membrane are elongated. The plasma membrane is frequently in intimate contact with the basement membrane. These cells have generally a large cytoplasmic expansion (Fig. 5).

scholarly journals Novel Roles for the Sirtuin Deacylase SIRT5 in Normal Physiology and in Cancer

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 741-741
Author(s):  
David Lombard
Keyword(s):  
Mitochondrial Matrix ◽  
Genomic Integrity ◽  
Biological Functions ◽  
Protein Targets ◽  
Post Translational Modifications ◽  
Catalytic Activities ◽  
Cellular Processes ◽  
Specific Cancer ◽  
Cancer Types ◽  
Chromatin Biology

Abstract Sirtuins are NAD+-dependent deacylases that regulate diverse cellular processes such as metabolic homeostasis and genomic integrity. Mammals possess seven sirtuin family members, SIRT1-SIRT7, that display diverse subcellular localization patterns, catalytic activities, protein targets, and biological functions. Three sirtuins, SIRT3, SIRT4, and SIRT5, are primarily located in the mitochondrial matrix. SIRT5 is a very inefficient deacetylase, instead removing negatively charged post-translational modifications (succinyl, glutaryl, and malonyl groups) from lysines of its target proteins, in mitochondria and throughout the cell. SIRT5 plays only modest known roles in normal physiology, with its major functions occurring in the heart under stress conditions. In contrast, in specific cancer types, including melanoma, we have identified a major pro-survival role for SIRT5. We have traced this function of SIRT5 to novel roles for this protein in regulating chromatin biology. New insights into mechanisms of SIRT5 action in cancer, and in normal myocardium, will be discussed.

scholarly journals Two-photon polymerization nanolithography technology for fabrication of stimulus-responsive micro/nano-structures for biomedical applications

2020 ◽  
Vol 9 (1) ◽  
pp. 1118-1136
Author(s):  
Zhenjia Huang ◽  
Gary Chi-Pong Tsui ◽  
Yu Deng ◽  
Chak-Yin Tang
Keyword(s):  
Biomedical Applications ◽  
Three Dimensional ◽  
Water Soluble ◽  
Fabrication Technology ◽  
Nano Fabrication ◽  
Two Photon ◽  
Nano Structures ◽  
Wide Range ◽  
Stimulus Responsive ◽  
Two Photon Polymerization

AbstractMicro/nano-fabrication technology via two-photon polymerization (TPP) nanolithography is a powerful and useful manufacturing tool that is capable of generating two dimensional (2D) to three dimensional (3D) arbitrary micro/nano-structures of various materials with a high spatial resolution. This technology has received tremendous interest in cell and tissue engineering and medical microdevices because of its remarkable fabrication capability for sophisticated structures from macro- to nano-scale, which are difficult to be achieved by traditional methods with limited microarchitecture controllability. To fabricate precisely designed 3D micro/nano-structures for biomedical applications via TPP nanolithography, the use of photoinitiators (PIs) and photoresists needs to be considered comprehensively and systematically. In this review, widely used commercially available PIs are first discussed, followed by elucidating synthesis strategies of water-soluble initiators for biomedical applications. In addition to the conventional photoresists, the distinctive properties of customized stimulus-responsive photoresists are discussed. Finally, current limitations and challenges in the material and fabrication aspects and an outlook for future prospects of TPP for biomedical applications based on different biocompatible photosensitive composites are discussed comprehensively. In all, this review provides a basic understanding of TPP technology and important roles of PIs and photoresists for fabricating high-precision stimulus-responsive micro/nano-structures for a wide range of biomedical applications.

Brush border myosin-I microinjected into cultured cells is targeted to actin-containing surface structures

1994 ◽  
Vol 107 (6) ◽  
pp. 1623-1631 ◽  
Author(s):  
M. Footer ◽  
A. Bretscher
Keyword(s):  
Plasma Membrane ◽  
Brush Border ◽  
Actin Filaments ◽  
Cultured Cells ◽  
Surface Structures ◽  
Specific Expression ◽  
Cultured Fibroblasts ◽  
Myosin I ◽  
Section Electron

The isolated intestinal microvillus cytoskeleton (core) consists of four major proteins: actin, villin, fimbrin and brush border myosin-I. These proteins can assemble in vitro into structures resembling native microvillus cores. Of these components, villin and brush border myosin-I show tissue-specific expression, so they may be involved in the morphogenesis of intestinal microvilli. When introduced into cultured cells that normally lack the protein, villin induces a reorganization of the actin filaments to generate large surface microvilli. Here we examine the consequences of microinjecting brush border myosin-I either alone or together with villin into cultured fibroblasts. Injection of brush border myosin-I has no discernible effect on the overall morphology of the cells, but does become localized to either normal or villin-induced microvilli and other surface structures containing an actin cytoskeleton. Since some endogenous myosin-Is have been found associated with cytoplasmic vesicles, these results show that brush border myosin-I has a domain that specifically targets it to the plasma membrane in both intestinal and cultured cell systems. Ultrastructural examination of microvilli on control cultured cells revealed that they contain a far more highly ordered bundle of microfilaments than had been previously appreciated. The actin filaments in microvilli of villin-injected cells appeared to be more tightly cross-linked when examined by thin-section electron microscopy. In intestinal microvilli, the core bundle is separated from the plasma membrane by about 30 nm due to the presence of brush border myosin-I.(ABSTRACT TRUNCATED AT 250 WORDS)

PI(4,5)P2 Clustering and Its Impact on Biological Functions

2021 ◽  
Vol 90 (1) ◽  
Author(s):  
Yi Wen ◽  
Volker M. Vogt ◽  
Gerald W. Feigenson
Keyword(s):  
Plasma Membrane ◽  
Cell Biology ◽  
Cellular Proteins ◽  
Annual Review ◽  
Publication Date ◽  
Biological Functions ◽  
Cellular Functions ◽  
Dynamic Distribution ◽  
Multivalent Cation ◽  
Lipid Environment

Located at the inner leaflet of the plasma membrane, phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] comprises only 1–2 mol% of total PM lipids. With its synthesis and turnover both spatially and temporally regulated, PI(4,5)P2 recruits and interacts with hundreds of cellular proteins to support a broad spectrum of cellular functions. Several factors contribute to the versatile and dynamic distribution of PI(4,5)P2 in membranes. Physiological multivalent cations such as Ca2+ and Mg2+ can bridge between PI(4,5)P2 headgroups, forming nanoscopic PI(4,5)P2–cation clusters. The distinct lipid environment surrounding PI(4,5)P2 affects the degree of PI(4,5)P2 clustering. In addition, diverse cellular proteins interacting with PI(4,5)P2 can further regulate PI(4,5)P2 lateral distribution and accessibility. This review summarizes the current understanding of PI(4,5)P2 behavior in both cells and model membranes, with emphasis on both multivalent cation– and protein-induced PI(4,5)P2 clustering. Understanding the nature of spatially separated pools of PI(4,5)P2 is fundamental to cell biology. Expected final online publication date for the Annual Review of Biochemistry, Volume 90 is June 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Review of Fabrication Methods of Nanotube / Nanowire Devices

2011 ◽  
Vol 411 ◽  
pp. 427-431 ◽  
Author(s):  
Miao Miao Tan ◽  
Zi Yi Zhang ◽  
Lin Hui Zhao ◽  
Jian Cheng Zhang
Keyword(s):  
Carbon Nanotube ◽  
High Performance ◽  
Chemical Properties ◽  
Research Field ◽  
Nano Materials ◽  
One Dimensional ◽  
Nano Fabrication ◽  
Nano Structures ◽  
Manufacturing Methods ◽  
And Chemical Properties

With the development of nano materials, a novel research field of NEMS forms by combining nano materials, nano-structures and nano fabrication with MEMS. Carbon nanotube (CNT) is a kind of one-dimensional nano structures which has unique mechanical, electrical and chemical properties. Using CNTs, new nano-devices with new principle or high performance would be developed. This paper reviews the assembly methods of one dimensional nanostructure and analyzes the characteristics of various methods, which provides reference for the device manufacturing methods using nanotubes/nanowires.

scholarly journals Lysosomal Exocytosis, Exosome Release and Secretory Autophagy: The Autophagic- and Endo-Lysosomal Systems Go Extracellular

2020 ◽  
Vol 21 (7) ◽  
pp. 2576 ◽  
Author(s):  
Sandra Buratta ◽  
Brunella Tancini ◽  
Krizia Sagini ◽  
Federica Delo ◽  
Elisabetta Chiaradia ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Molecular Mechanisms ◽  
Current Knowledge ◽  
Cell Communication ◽  
Lysosomal Storage ◽  
Cellular Processes ◽  
Age Related ◽  
Extracellular Release ◽  
A Cell ◽  
Endosomal System

Beyond the consolidated role in degrading and recycling cellular waste, the autophagic- and endo-lysosomal systems play a crucial role in extracellular release pathways. Lysosomal exocytosis is a process leading to the secretion of lysosomal content upon lysosome fusion with plasma membrane and is an important mechanism of cellular clearance, necessary to maintain cell fitness. Exosomes are a class of extracellular vesicles originating from the inward budding of the membrane of late endosomes, which may not fuse with lysosomes but be released extracellularly upon exocytosis. In addition to garbage disposal tools, they are now considered a cell-to-cell communication mechanism. Autophagy is a cellular process leading to sequestration of cytosolic cargoes for their degradation within lysosomes. However, the autophagic machinery is also involved in unconventional protein secretion and autophagy-dependent secretion, which are fundamental mechanisms for toxic protein disposal, immune signalling and pathogen surveillance. These cellular processes underline the crosstalk between the autophagic and the endosomal system and indicate an intersection between degradative and secretory functions. Further, they suggest that the molecular mechanisms underlying fusion, either with lysosomes or plasma membrane, are key determinants to maintain cell homeostasis upon stressing stimuli. When they fail, the accumulation of undigested substrates leads to pathological consequences, as indicated by the involvement of autophagic and lysosomal alteration in human diseases, namely lysosomal storage disorders, age-related neurodegenerative diseases and cancer. In this paper, we reviewed the current knowledge on the functional role of extracellular release pathways involving lysosomes and the autophagic- and endo-lysosomal systems, evaluating their implication in health and disease.

Fabrication of Nano-Electromechanical Structures Down to 20 nm by Spacer Technology

2007 ◽  
Author(s):  
Xiang Han ◽  
Ling Xia ◽  
Wengang Wu ◽  
Guizhen Yan ◽  
Jun Xu ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Mechanical Vibration ◽  
Cantilever Beams ◽  
Fabrication Method ◽  
Feature Size ◽  
Plasma Damage ◽  
Nano Fabrication ◽  
Nano Structures ◽  
20 Nm ◽  
Deposited Film

Spacer technology has been developed to fabricate nano-structures for NEMS application. It provides a parallel nano-fabrication method with double or quadplex device density at a certain lithography node. By controlling the deposited film thickness, the feature size of the SiO2 spacer hard mask is reduced down to 35 nm. After the spacer pattern is transferred to Si, a precise thermal oxidation is performed to improve the profile and reduce the plasma damage. Finally, sublimation or HF vapor phase etching is introduced to release the nano-structures according to different structure dimensions. As a result, with better surface morphology, suspended Si nano-beams with a width of 20 nm are obtained. Actuated by mechanical vibration and electrostatic forces, vibrations of the obtained cantilever beams and fixed-fixed beams are observed in SEM. In addition, a metallic nano-nozzle with a diameter of 140 nm is established by electroless plating around the suspended Si nano-beam served as a mold. As a development of the spacer technology, nano-needle array is demonstrated at the cross points of crossed SiO2 spacers by anisotropic etching. The diameters of the hybridized nano-needles are 300 nm so far and can be further reduced by smaller spacer dimension.

scholarly journals Advances in the role of m6A RNA modification in cancer metabolic reprogramming

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Xiu Han ◽  
Lin Wang ◽  
Qingzhen Han
Keyword(s):  
Cancer Cells ◽  
Epigenetic Modification ◽  
Metabolic Reprogramming ◽  
Regulatory Mechanisms ◽  
Rna Modification ◽  
Biological Functions ◽  
Rna Transcription ◽  
Cellular Processes ◽  
Metabolic Genes

Abstract N6-methyladenosine (m6A) modification is the most common internal modification of eukaryotic mRNA and is widely involved in many cellular processes, such as RNA transcription, splicing, nuclear transport, degradation, and translation. m6A has been shown to plays important roles in the initiation and progression of various cancers. The altered metabolic programming of cancer cells promotes their cell-autonomous proliferation and survival, leading to an indispensable hallmark of cancers. Accumulating evidence has demonstrated that this epigenetic modification exerts extensive effects on the cancer metabolic network by either directly regulating the expression of metabolic genes or modulating metabolism-associated signaling pathways. In this review, we summarized the regulatory mechanisms and biological functions of m6A and its role in cancer metabolic reprogramming.

scholarly journals Plasma Membrane Protein Nce102 Modulates Morphology and Function of the Yeast Vacuole

Biomolecules ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1476
Author(s):  
Katarina Vaskovicova ◽  
Petra Vesela ◽  
Jakub Zahumensky ◽  
Dagmar Folkova ◽  
Maria Balazova ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Vacuolar Membrane ◽  
Yeast Culture ◽  
Membrane Domains ◽  
Biological Functions ◽  
Plasma Membrane Protein ◽  
Cell Architecture ◽  
And Function

Membrane proteins are targeted not only to specific membranes in the cell architecture, but also to distinct lateral microdomains within individual membranes to properly execute their biological functions. Yeast tetraspan protein Nce102 has been shown to migrate between such microdomains within the plasma membrane in response to an acute drop in sphingolipid levels. Combining microscopy and biochemistry methods, we show that upon gradual ageing of a yeast culture, when sphingolipid demand increases, Nce102 migrates from the plasma membrane to the vacuole. Instead of being targeted for degradation it localizes to V-ATPase-poor, i.e., ergosterol-enriched, domains of the vacuolar membrane, analogous to its plasma membrane localization. We discovered that, together with its homologue Fhn1, Nce102 modulates vacuolar morphology, dynamics, and physiology. Specifically, the fusing of vacuoles, accompanying a switch of fermenting yeast culture to respiration, is retarded in the strain missing both proteins. Furthermore, the absence of either causes an enlargement of ergosterol-rich vacuolar membrane domains, while the vacuoles themselves become smaller. Our results clearly show decreased stability of the V-ATPase in the absence of either Nce102 or Fhn1, a possible result of the disruption of normal microdomain morphology of the vacuolar membrane. Therefore, the functionality of the vacuole as a whole might be compromised in these cells.

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