transmission electron microscopy
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2022 ◽  
Adrian Deichsel ◽  
Anna Giuseppe ◽  
Isabel Zeinert ◽  
Kerstin Katharina Rauwolf ◽  
Ning Lu ◽  

Background: In rheumatoid arthritis (RA), fibroblast-like synoviocytes (FLS) undergo a tumor-like transformation, wherein they develop an aggressive phenotype that is characterized by increased adhesion to components of cartilage extracellular matrix (ECM) and that contributes extensively to joint destruction. The collagen-binding integrin alpha11beta1 was previously shown to be involved in similar processes in cancer-associated fibroblasts mediating tumorigenicity and metastasis in certain tumors. Therefore, this study aimed to study the role of integrin alpha11beta1 in RA and to characterize the effects of alpha11beta1 deficiency on the disease course and severity in arthritic hTNFtg mice. Methods: The expression levels of integrin alpha11beta1 were analyzed by immunohistochemistry, immunofluorescence, and western blot analysis in synovial samples and FLS of patients with RA and osteoarthritis (OA) as well as in samples from wild type (wt) and arthritic hTNFtg mice. Furthermore, the subcellular expression of integrin alpha11beta1 was investigated in co-culture experiments with cartilage explants and analyzed by transmission electron microscopy. To investigate the effects of integrin alpha11beta1 deficiency, itga11-/- mice were interbred with hTNFtg mice and disease severity was assessed by clinical scoring of grip strength and paw swelling over the disease course. Hind paws of 12-weeks-old mice of all genotypes were analyzed by uCT imaging followed by stainings of paraffin-embedded tissue sections with Toluidine-blue and tartrate-resistant acid phosphatase (TRAP) to evaluate established parameters of joint destruction such as inflammation area, cartilage destaining, FLS attachment to the cartilage surface, and bone damage. Results: Expression levels of integrin alpha11beta1 were clearly elevated in synovial tissues and FLS from RA patients and hTNFtg mice, compared to the controls derived from OA patients and wt mice. Interestingly, this expression was shown to be particularly localized in focal adhesions of the FLS. As revealed by transmission electron microscopy, integrin alpha11beta1 expression was particularly evident in areas of direct cellular contact with the ECM of cartilage. Evaluations of clinical scorings and histomorphological analyses demonstrated that itga11-/-hTNFtg displayed alleviated clinical symptoms, higher bone volume, less cartilage destruction, and reduced FLS attachment to the cartilage in comparison to hTNFtg mice. Conclusions: The collagen-binding integrin alpha11beta1 is upregulated in the context of RA and its deficiency in mice with an inflammatory hTNFtg background leads to a significant reduction in the arthritic phenotype which makes integrin alpha11beta1 an interesting target for therapeutical intervention.

2022 ◽  
Vol 12 ◽  
Dai Zhang ◽  
Ran Qiang ◽  
Jing Zhao ◽  
Jinglin Zhang ◽  
Jianing Cheng ◽  

The antagonistic mechanisms of soluble non-volatile bioactive compounds, such as proteins and lipopeptides emitted from Bacillus have been widely studied. However, there are limited studies on the antifungal mechanisms of volatile organic compounds (VOCs) produced by Bacillus against plant fungal diseases. In this study, the antagonistic mechanisms of one specific VOC, 6-methyl-2-heptanone, against Alternaria solani were investigated. To optimize the extraction conditions of headspace solid-phase microextraction, a 50/30-μm divinylbenzene/carboxen/polydimethylsiloxane fiber at 50°C for 40 min was used. For gas chromatography-mass spectrometry using a free fatty acid phase capillary column, 6-methyl-2-heptanone accounted for the highest content, at 22.27%, of the total VOCs from Bacillus subtilis ZD01, which inhibited A. solani mycelial growth strongly in vitro. Therefore, 6-methyl-2-heptanone was selected as the main active chemical to elucidate the action mechanisms against A. solani. Scanning and transmission electron microscopy analyses revealed that after exposure to an EC50 dose of 6-methyl-2-heptanone, A. solani hyphal cells had a wide range of abnormalities. 6-Methyl-2-heptanone also caused the capture of cellular fluorescent green label and the release of adenosine triphosphate (ATP) from outer membranes A. solani cells, which may enhance 6-methyl-2-heptanone ability to reach the cytoplasmic membrane. In addition, 6-methyl-2-heptanone showed strong inhibitory effect on A. solani conidial germination. It also damaged conidial internal structures, with the treated group having collapsed shrunken small vesicles as observed by transmission electron microscopy. Because 6-methyl-2-heptanone showed strong effects on mycelial integrity and conidial structure, the expression levels of related pathogenic genes in A. solani treated with 6-methyl-2-heptanone were investigated. The qRT-PCR results showed that transcriptional expression levels of slt2 and wetA genes were strongly down-regulated after exposure to 6-methyl-2-heptanone. Finally, because identifying the functions of pathogenic genes will be important for the biological control of A. solani, the wetA gene was identified as a conidia-associated gene that plays roles in regulating sporulation yield and conidial maturation. These findings provide further insights into the mechanisms of VOCs secreted by Bacillus against A. solani.

2022 ◽  
Vol 13 (1) ◽  
Binbin Chen ◽  
Nicolas Gauquelin ◽  
Nives Strkalj ◽  
Sizhao Huang ◽  
Ufuk Halisdemir ◽  

AbstractIn order to bring the diverse functionalities of transition metal oxides into modern electronics, it is imperative to integrate oxide films with controllable properties onto the silicon platform. Here, we present asymmetric LaMnO3/BaTiO3/SrTiO3 superlattices fabricated on silicon with layer thickness control at the unit-cell level. By harnessing the coherent strain between the constituent layers, we overcome the biaxial thermal tension from silicon and stabilize c-axis oriented BaTiO3 layers with substantially enhanced tetragonality, as revealed by atomically resolved scanning transmission electron microscopy. Optical second harmonic generation measurements signify a predominant out-of-plane polarized state with strongly enhanced net polarization in the tricolor superlattices, as compared to the BaTiO3 single film and conventional BaTiO3/SrTiO3 superlattice grown on silicon. Meanwhile, this coherent strain in turn suppresses the magnetism of LaMnO3 as the thickness of BaTiO3 increases. Our study raises the prospect of designing artificial oxide superlattices on silicon with tailored functionalities.

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 510
Xin F. Tan ◽  
Flora Somidin ◽  
Stuart D. McDonald ◽  
Michael J. Bermingham ◽  
Hiroshi Maeno ◽  

The complex reaction between liquid solder alloys and solid substrates has been studied ex-situ in a few studies, utilizing creative setups to “freeze” the reactions at different stages during the reflow soldering process. However, full understanding of the dynamics of the process is difficult due to the lack of direct observation at micro- and nano-meter resolutions. In this study, high voltage transmission electron microscopy (HV-TEM) is employed to observe the morphological changes that occur in Cu6Sn5 between a Sn-3.0 wt%Ag-0.5 wt%Cu (SAC305) solder alloy and a Cu substrate in situ at temperatures above the solidus of the alloy. This enables the continuous surveillance of rapid grain boundary movements of Cu6Sn5 during soldering and increases the fundamental understanding of reaction mechanisms in solder solid/liquid interfaces.

Nano Letters ◽  
2022 ◽  
Chao Zhang ◽  
Konstantin V. Larionov ◽  
Konstantin L. Firestein ◽  
Joseph F. S. Fernando ◽  
Courtney-Elyce Lewis ◽  

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 193
Kamrun Nahar Fatema ◽  
Chang-Sung Lim ◽  
Yin Liu ◽  
Kwang-Youn Cho ◽  
Chong-Hun Jung ◽  

We described the novel nanocomposite of silver doped ZrO2 combined graphene-based mesoporous silica (ZrO2-Ag-G-SiO2,) in bases of low-cost and self-assembly strategy. Synthesized ZrO2-Ag-G-SiO2 were characterized through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDX), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Raman spectroscopy, Nitrogen adsorption-desorption isotherms, X-ray photoelectron spectroscopy (XPS), and Diffuse Reflectance Spectroscopy (DRS). The ZrO2-Ag-G-SiO2 as an enzyme-free glucose sensor active material toward coordinate electro-oxidation of glucose was considered through cyclic voltammetry in significant electrolytes, such as phosphate buffer (PBS) at pH 7.4 and commercial urine. Utilizing ZrO2-Ag-G-SiO2, glucose detecting may well be finished with effective electrocatalytic performance toward organically important concentrations with the current reaction of 9.0 × 10−3 mAcm−2 and 0.05 mmol/L at the lowest potential of +0.2 V, thus fulfilling the elemental prerequisites for glucose detecting within the urine. Likewise, the ZrO2-Ag-G-SiO2 electrode can be worked for glucose detecting within the interferometer substances (e.g., ascorbic corrosive, lactose, fructose, and starch) in urine at proper pH conditions. Our results highlight the potential usages for qualitative and quantitative electrochemical investigation of glucose through the ZrO2-Ag-G-SiO2 sensor for glucose detecting within the urine concentration.

Small ◽  
2022 ◽  
pp. 2106411
Yi‐Tang Tseng ◽  
Li‐Syuan Lu ◽  
Fang‐Chun Shen ◽  
Che‐Hung Wang ◽  
Hsin‐Ya Sung ◽  

Biology Open ◽  
2022 ◽  
Takuma Kozono ◽  
Miwa Tamura-Nakano ◽  
Yuki I. Kawamura ◽  
Takashi Tonozuka ◽  
Atsushi Nishikawa

Tuft cell is a chemosensory cell, a specific cell type sharing the taste transduction system with a taste cell on the tongue, of which the existence has been known in various tissues such as gastrointestinal tract, gall bladder, trachea, pancreatic duct, etc. To date, electron microscopic approaches have shown various morphological features of the tuft cell such as long and thick microvilli, tubulovesicular network at the apical side, prominent skeleton structures, etc. Recently, it has been reported that the small intestinal tuft cell functions to initiate type2 immunity in response to helminth infection. However, the mechanisms by which such distinguished structures are involved with the physiological functions are poorly understood. To address this question, the combination of physiological study regarding the tuft cells using genetic models and its morphological study using electron microscopy will be required. However, it is a challenge to observe tuft cells by electron microscopy due to their extremely low frequency on the epithelium. Therefore, in this paper, we suggest the advanced protocol to observe the small intestinal tuft cell efficiently by transmission electron microscopy using serial semi-thin sections on the Aclar film.

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