Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 34
Filter
1.
Virol J ; 21(1): 64, 2024 03 11.
Article in English | MEDLINE | ID: mdl-38468354

ABSTRACT

OBJECTIVE: Canine enteric coronavirus (CCV) and canine parvovirus type 2 (CPV-2) are the main pathogens responsible for acute gastroenteritis in dogs, and both single and mixed infections are common. This study aimed to establish a double-labeling time-resolved fluorescence immunoassay (TRFIA) to test and distinguish CCV and CPV-2 diseases. METHODS: A sandwich double-labeling TRFIA method was established and optimized using europium(III) (Eu3+)/samarium(III) (Sm3+) chelates. CCV/CPV-2 antigens were first captured by the immobilized antibodies. Then, combined with Eu3+/Sm3+-labeled paired antibodies, the Eu3+/Sm3+ fluorescence values were detected after dissociation to calculate the CCV/CPV-2 ratios. The performance, clinical performance and methodology used for laboratory (sensitivity, specificity, accuracy and stability) testing were evaluated. RESULTS: A double-label TRFIA for CCV and CPV-2 detection was optimized and established. The sensitivity of this TRFIA kit was 0.51 ng/mL for CCV and 0.80 ng/mL for CPV-2, with high specificity for CCV and CPV-2. All the accuracy data were less than 10%, and the recovery ranged from 101.21 to 110.28%. The kits can be temporarily stored for 20 days at 4 °C and can be stored for 12 months at temperatures less than - 20 °C. Based on a methodology comparison of 137 clinically suspected patients, there was no statistically significant difference between the TRFIA kit and the PCR method. Additionally, for CCV detection, the clinical sensitivity was 95.74%, and the clinical specificity was 93.33%. For CPV-2 detection, the clinical sensitivity was 92.86%, and the clinical specificity was 96.97%. CONCLUSION: In this study, a double-label TRFIA kit was prepared for CCV and CPV-2 detection with high laboratory sensitivity, specificity, accuracy, stability, clinical sensitivity and specificity. This kit provides a new option for screening/distinguishing between CCV and CPV-2 and may help improve strategies to prevent and control animal infectious diseases in the future.


Subject(s)
Coronavirus, Canine , Dog Diseases , Parvoviridae Infections , Parvovirus, Canine , Humans , Animals , Dogs , Parvoviridae Infections/diagnosis , Parvoviridae Infections/veterinary , Sensitivity and Specificity , Immunoassay , Dog Diseases/diagnosis
2.
Chem Asian J ; 18(3): e202201063, 2023 Feb 01.
Article in English | MEDLINE | ID: mdl-36530060

ABSTRACT

D-labeling is a valuable tool in advanced synthetic chemistry and pharmacy. However, D-incorporation significantly complicates the identification of products. In fact, D labels are invisible in 1 H-NMR spectra and cause undesirable splitting in 13 C-NMR spectra which decreases the detectable limits. At the same time, 2 H-NMR spectra are not effective for precise identification due to low sensitivity and the absence of correlations with 1 H atoms. Here, 13 C-label was considered as an accompanying label for D-label in [13 C+D] unit for identification of D-containing sites and to track D-labels. [13 C+D]-doubly labeled vinyl derivatives and triazoles were synthesized using 13 C-labeled calcium carbide as a source of 13 C-label and deuterium oxide as a source of D-label. The reaction occurred in one-step manner accompanied with in situ doubly labeled acetylene formation. Non-labeled, mono-labeled and doubly labeled substrates were isolated in 25-80% yields.

3.
Pol J Vet Sci ; 25(2): 287-294, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35861991

ABSTRACT

Thymus, an important central immune organ in pigs, is the site of T lymphocyte development and maturation and an important target organ for infection and replication of various pathogens. Highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) infection results in severe thymic atrophy in piglets. This study aimed to explore the effects of HP-PRRSV on the thymic structure of piglets to elucidate the pathogenesis of thymic atrophy induced by HP-PRRSV. In this study, histopathological techniques and immunofluorescence double staining techniques were used to analyze thymic tissues infected by HP-PRRSV to explore the structural changes of thymus caused by the viral infection and its target cell types. An antibody of cluster of differentiation (CD) 3 (CD3), CD20, CD80, or calgranulin + calprotectin was applied to identify T cells, B cells, dendritic cells (DCs), and macrophages, respectively. The results indicated that a variety of cell components in the thymic tissue were diffusely damaged after viral infection. In the infected thymic tissue, CD80- or calgranulin + calprotectin- -labeled cells supported the HP-PRRSV infection, whereas CD3-labeled T cells and CD20- -labeled B cells did not support the viral infection. The results showed that HP-PRRSV caused the reduction of visible cell components in the thymic tissue, and the virus attacked CD80- and calgranulin + calprotectin-positive cells (such as DCs and macrophages) in the thymic tissue, which played an important role in the pathogenesis of thymus atrophy. These results lay the foundation for elucidating the immunosuppression of piglets after infection with HP-PRRSV.


Subject(s)
Porcine Reproductive and Respiratory Syndrome , Porcine respiratory and reproductive syndrome virus , Swine Diseases , Animals , Atrophy/pathology , Atrophy/veterinary , Leukocyte L1 Antigen Complex , Swine , Swine Diseases/pathology , T-Lymphocytes
4.
J Clin Exp Hematop ; 60(3): 108-112, 2020.
Article in English | MEDLINE | ID: mdl-32981914

ABSTRACT

We report an autopsy case of acute myocarditis, in which the mediastinal lymph nodes exhibited unique findings. A 15-year-old Japanese boy was diagnosed with the secondary onset of acute myocarditis. No viruses were identified. Autopsy confirmed acute lymphocytic myocarditis. Lymphadenopathy was observed, especially in pulmonary hilar/mediastinal areas. Microscopically, interfollicular areas were uniformly filled with medium-sized, round cells that resembled lymphocytes. They were immunohistochemically CD3- CD5- CD19+ CD20- CD79a- Pax-5- CD138+ MUM1+ LMP1- EBNA2- cytoplasmic IgG+ IgA- and IgM-. No monotypia was observed for kappa and lambda light chains, and multiplex polymerase chain reaction analyses of immunoglobulin heavy chain variable region diversity demonstrated oligoclonal peaks, suggesting reactive change. IgG+ or VS38c+ cells frequently co-expressed Ki-67 (up to 80%). We considered these cells abundantly present in lymph nodes to be reactive plasmablasts because they were early plasma cells with proliferative activity.


Subject(s)
Lymph Nodes/pathology , Myocarditis/pathology , Acute Disease , Adolescent , Antigens, CD/analysis , Autopsy , Cell Proliferation , Humans , Lymph Nodes/cytology , Male , Plasma Cells/cytology , Plasma Cells/pathology
5.
Biosci Rep ; 40(6)2020 06 26.
Article in English | MEDLINE | ID: mdl-32452512

ABSTRACT

The fragile X mental retardation protein (FMRP) is a regulator of local translation through its mRNA targets in the neurons. Previous studies have demonstrated that FMRP may function in distinct ways during the development of different visual subcircuits. However, the localization of the FMRP in different types of retinal cells is unclear. In this work, the FMRP expression in rat retina was detected by Western blot and immunofluorescence double labeling. Results showed that the FMRP expression could be detected in rat retina and that the FMRP had a strong immunoreaction (IR) in the ganglion cell (GC) layer, inner nucleus layer (INL), and outer plexiform layer (OPL) of rat retina. In the outer retina, the bipolar cells (BCs) labeled by homeobox protein ChX10 (ChX10) and the horizontal cells (HCs) labeled by calbindin (CB) were FMRP-positive. In the inner retina, GABAergic amacrine cells (ACs) labeled by glutamate decarbonylase colocalized with the FMRP. The dopaminergic ACs (tyrosine hydroxylase marker) and cholinergic ACs (choline acetyltransferase (ChAT) marker) were co-labeled with the FMRP. In most GCs (labeled by Brn3a) and melanopsin-positive intrinsically photosensitive retinal GCs (ipRGCs) were also FMRP-positive. The FMRP expression was observed in the cellular retinal binding protein-positive Müller cells. These results suggest that the FMRP could be involved in the visual pathway transmission.


Subject(s)
Fragile X Mental Retardation Protein/metabolism , Retinal Neurons/metabolism , Amacrine Cells/metabolism , Animals , Biomarkers/metabolism , Ependymoglial Cells/metabolism , Fragile X Mental Retardation Protein/genetics , Immunohistochemistry , Male , Mice, Inbred C57BL , Mice, Knockout , Rats, Sprague-Dawley , Retinal Bipolar Cells/metabolism , Retinal Ganglion Cells/metabolism , Retinal Horizontal Cells/metabolism , Vision, Ocular
6.
Neuropharmacology ; 166: 107973, 2020 04.
Article in English | MEDLINE | ID: mdl-32006904

ABSTRACT

Nitric oxide (NO) release in the right medial prefrontal cortex (RmPFC) produces anxiogenesis. In the bed nucleus of the stria terminalis (BNST), a region that receives neuronal projections from the mPFC, NO provokes anxiety, an effect that is blocked by local injections of corticotrophin-releasing factor type 1 receptor (CRF1) or n-methyl-d-aspartate receptor (NMDAr) antagonist. Anxiety is also enhanced by social defeat stress, and chronic stress impairs and facilitates, respectively, PFC and BNST roles in modulating behavioral responses to aversive situations. This study investigated whether the (i) chronic social defeat stress (CSDS) increases NO signaling in the mPFC; and/or (ii) anxiogenic effects provoked by the intra-RmPFC injection of NOC-9 (an NO donor) or by CSDS are prevented by intra-BNST injections of AP-7 (0.05 nmol) or CP 376395 (3.0 nmol), respectively, NMDAr and CRF1 antagonists, in male Swiss-Webster mice exposed to the elevated plus-maze (EPM). Results showed that (a) CSDS increased anxiety (i.e., reduced open-arm exploration) and repeatedly activated nNOS-containing neurons, as measured by ΔFosB (a stable nonspecific marker of neural activity) + nNOS double-labeling, in the right (but not left) mPFC, (b) NOC-9 in the RmPFC also increased anxiety, and (c) both CSDS and NOC-9 effects were reversed by injections of AP-7 or CP 376395 into the BNST. These results suggest that NMDA and CRF1 receptors located in BNST play an important role in the modulation of anxiety provoked by NO in the RmPFC, as well as by chronic social defeat in mice.


Subject(s)
Anxiety/metabolism , Nitric Oxide/metabolism , Prefrontal Cortex/metabolism , Receptors, Corticotropin-Releasing Hormone/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism , Septal Nuclei/metabolism , Social Defeat , Aminopyridines/administration & dosage , Animals , Anxiety/chemically induced , Anxiety/psychology , Male , Maze Learning/drug effects , Maze Learning/physiology , Mice , Microinjections , Nitric Oxide/toxicity , Prefrontal Cortex/drug effects , Receptors, Corticotropin-Releasing Hormone/antagonists & inhibitors , Receptors, N-Methyl-D-Aspartate/antagonists & inhibitors , Septal Nuclei/drug effects , Triazenes/administration & dosage
7.
Diagn Pathol ; 14(1): 9, 2019 Feb 02.
Article in English | MEDLINE | ID: mdl-30711015

ABSTRACT

BACKGROUND: Pagetoid spread of urothelial carcinoma (UC) to the lower genital tract is quite a rare and diagnostically challenging condition. Pagetoid urothelial intraepithelial neoplasia extending to the vagina is difficult to diagnose, especially in remote recurrences without symptomatic or macroscopic lesions typical to Paget disease. However, its identification by cervical screening cytology is important because UC is often characterized by a long history of relapse. CASE PRESENTATION: A 68-year-old Japanese postmenopausal woman developed brown vaginal discharge after radical cystectomy for bladder cancer (high-grade UC, pT2a pN0 cM0 [Union for International Cancer Control, 8th edition]) concomitant with focal in-situ UC in the urethra. She had a history of left renal pelvis UC, which was surgically removed 9 months before the radical cystectomy. Gynecologic examination of the lower genital tract was unremarkable although cervical screening cytology demonstrated severely atypical cells with pleomorphism repeatedly. Cervical colposcopy and diagnostic conization revealed no cervical neoplasm. In retrospect, immunocytochemical p16/Ki-67 dual staining for the previous cervical screening was negative for p16 labeling, and the neoplastic cells were positive for cytokeratins 7 and 20, p63, and GATA binding protein 3. No high-risk human papillomavirus genotype was identified by an automated DNA chip system using liquid-based cytology samples. Eleven months post-cystectomy, punch biopsy of the vulva and vagina confirmed intraepithelial UC in the juxtaposed squamous epithelium with pagetoid spread demonstrating positivity for specific urothelial markers: uroplakins II and III and thrombomodulin. Concurrent invasive malignancy was ruled out, and CO2 laser vaporization of the vulvar and vaginal lesion was performed. The patient remained alive without evidence of invasive malignancy for 14 months after the radical cystectomy for bladder cancer. CONCLUSIONS: To detect recurrent pagetoid urothelial intraepithelial neoplasia with pagetoid spread in the lower genital tract, pathologists should recognize the history of prior UC with special attention to absence of p16 labeling in cervical cytology as a pointer to the diagnosis of urothelial cancer. Using further biopsy and immunohistochemical confirmation of UC relapse, investigation to rule out invasive malignancies and careful follow-up throughout the patient's lifetime is recommended.


Subject(s)
Carcinoma in Situ/diagnosis , Carcinoma, Transitional Cell/diagnosis , Urinary Bladder Neoplasms/pathology , Aged , Biopsy , Carcinoma in Situ/pathology , Carcinoma, Transitional Cell/pathology , Cystectomy , Female , Humans , Immunohistochemistry , Nephroureterectomy , Treatment Outcome , Urinary Bladder Neoplasms/surgery , Vagina/pathology , Vulva/pathology
8.
Virus Res ; 260: 78-85, 2019 01 15.
Article in English | MEDLINE | ID: mdl-30472093

ABSTRACT

Nervous necrosis virus (NNV) belongs to the genus Betanodavirus of family Nodaviridae. Its genome consists of two RNA segments, RNA1 and RNA2. Several studies have investigated NNV detection by in situ hybridization (ISH), but these have typically focused on the detection of the RNA2 gene. In this study, we localized both RNA1 and RNA2 NNV segments in viral-infected cells by ISH, using labeled RNA probes (RNA-ISH). Also, immunocytochemistry (ICC) assay was carried out for localization of viral particle by targeting the coat protein. Further, viral quantification assays were performed by quantitative RT-PCR and viral infectivity (TCID50) in SSN-1 cells. Viral segments were observed by RNA-ISH at 6 h post infection (hpi), while NNV particles were detected at 24 hpi by ICC. Use of double labeling RNA-ISH revealed the co-expression of the two viral segments in the same area of the cells, while RNA1 was also detected separately. Comparison of the level of viral genomic segments and viral infectivity revealed significantly more copies of RNA1 at each time points than copies of RNA2 and greater NNV titers. The results suggest that RNA1 might be expressed in the early stages of replication, with RNA2 expressed later. The virions then assemble through initially expressed viral genomic segments. Even though infectious particles displayed very efficient packaging, the RNA1 segment was still over-produced.


Subject(s)
Nodaviridae/physiology , RNA, Viral/analysis , Virus Replication , Animals , Capsid Proteins/analysis , Capsid Proteins/immunology , Cell Line , Fishes , Immunohistochemistry , In Situ Hybridization , Nodaviridae/genetics , RNA, Viral/genetics , Real-Time Polymerase Chain Reaction , Viral Load
9.
Chembiochem ; 20(5): 659-666, 2019 03 01.
Article in English | MEDLINE | ID: mdl-30427570

ABSTRACT

Conjugation of fluorescent dyes to proteins-a prerequisite for the study of conformational dynamics by single-molecule (sm) FRET-can lead to substantial changes in a dye's photophysical properties, ultimately biasing the determination of inter-dye distances. In particular, cyanine dyes and their derivatives, the most commonly used dyes in smFRET experiments, exhibit such behavior. To overcome this, we developed a general strategy to equip proteins site-specifically with FRET pairs through chemoselective reactions with two distinct noncanonical amino acids simultaneously incorporated through genetic code expansion in Escherichia coli. Application of this technique to human NADPH-cytochrome P450 reductase (CPR) demonstrated the importance of homogenously labeled samples for accurate determination of FRET efficiencies and unveiled the effect of NADP+ on the ionic-strength-dependent modulation of the conformational equilibrium of CPR. Thanks to its generality and accuracy, the presented methodology establishes a new benchmark for deciphering of complex molecular dynamics in single molecules.


Subject(s)
Fluorescence Resonance Energy Transfer/methods , NADPH-Ferrihemoprotein Reductase/chemistry , Single Molecule Imaging/methods , Carbocyanines/chemistry , Cloning, Molecular , Escherichia coli/genetics , Fluorescent Dyes/chemistry , Humans , Lysine/analogs & derivatives , Lysine/chemistry , Microscopy, Confocal/methods , Molecular Conformation , Phenylalanine/analogs & derivatives , Phenylalanine/chemistry
10.
J Proteomics ; 194: 89-98, 2019 03 01.
Article in English | MEDLINE | ID: mdl-30553074

ABSTRACT

Stable isotope labeling with amino acids in cell culture (SILAC) is a robust proteomics method with advantages such as reproducibility and easy handling. This method is popular for the analysis of mammalian cells. However, amino acid conversion in bacteria decreases the labeling efficiency and quantification accuracy, limiting the application of SILAC in bacterial proteomics to auxotrophic bacteria or to single labeling with lysine. In this study, we found that adding high concentrations of isotope-labeled (heavy) and natural (light) amino acids into SILAC minimal medium can efficiently inhibit the complicated amino acid conversions. This simple and straightforward strategy facilitated complete incorporation of amino acids into the bacterial proteome with good accuracy. High labeling efficiency can be achieved in different bacteria by slightly modifying the supplementation of amino acids in culture media, promoting the widespread application of SILAC technique in bacterial proteomics. SIGNIFICANCE: Amino acid conversion in bacteria decreases labeling efficiency, limiting the application of Stable isotope labeling with amino acids in cell culture (SILAC) in bacterial proteomics to auxotrophic bacteria or single labeling with lysine. In this study, we found that high concentrations of isotope-labeled (heavy) and natural (light) amino acids facilitate full incorporation of amino acids into the bacterial proteome with good reproducibility. This improved double labeling SILAC technique using medium supplemented with high concentrations of amino acids is suitable for quantitative proteomics research on both gram-positive and -negative bacteria, facilitating the broad application of quantitative proteomics in bacterial studies.


Subject(s)
Bacteria/metabolism , Bacterial Proteins/metabolism , Isotope Labeling/methods , Proteome/metabolism , Proteomics
11.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-823892

ABSTRACT

Objective To investigate the corneal permeability of cyclosprin A (CsA) loaded on polymeric vector after topical application.Methods The grafted copolymer chitosan-graft-cyclodextrin (CS-g-CD) was synthesized,and the physicochemical structures of the polymer were investigated using nuclear magnetic resonance spectroscopy (NMR) and fourier transform infrared spectroscopy (FT-IR).A novel CsA eye drop was prepared using the grafted copolymer as carrier material.The physicochemical properties of eye drop,including drug-loading content,osmotic pressure and viscosity were investigated by high performance liquid chromatography-mass spectrometry (HPLC-MS),osmotic pressure gauge and viscometer,respectively.New Zealand albino rabbits were randomly divided into intact cornea CsA group,epithelium debrided CsA group and epithelium debrided control group.The corneal epithelia of the left eyes was debrided in the cornea epithelium debrided group.Cornea irritation test was performed on New Zealand albino rabbits.The aqueous humor was taken and the corneas were collected at 0.5 hour and 1 hour after instilled.The concentration of CsA was measured by HPLC-MS.Cy5 labeled vector loaded with Coumarin 6 served as model copolymers system,the penetration capabilities of the double fluorescent labeling copolymers system were monitored in vivo using two-photon scanning fluorescence microscopy on murine corneas after topical application.The use and care of the animals complied with Regulations for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission.Results The polymer of CS-g-CD was successfully synthesized and confirmed using NMR and FT-IR.The drug loading of CsA in eye drop solution was 0.06 %;the osmotic pressure was 305 mOsmol/kg and the viscosity was 36.5 cP.The CsA drug delivery system had a reversible temperature-sensitive drug release behavior and had no obvious irritation on the eyes of New Zealand rabbits.One hour after treatment,the concentration of CsA in the cornea and aqueous humor of epithelium debrided CsA group was (5.88 ± 1.46) μg/g and (149.19 ± 3.93) ng/ml,respectively,which was significantly higher than (3.98 ±0.95) μg/g and (30.25± 11.43) ng/ml in epithelium debrided control group (both at P<0.05);the concentration of CsA in the aqueous humor of intact cornea CsA group was (7.23 ± 1.31)ng/ml,which was significantly lower than that in epithelium debrided CsA group (P<0.05).Polymer vectors were mainly retained in the corneal epithelium,and coumarin 6 gradually diffused into the deep corneal stroma with time.Conclusions The grafted copolymer can load CsA,and the eye drop can effectively overcome the corneal barrier and increase the corneal permeability of CsA.

12.
Mol Cell Probes ; 42: 18-24, 2018 12.
Article in English | MEDLINE | ID: mdl-30343149

ABSTRACT

In situ hybridization (ISH) of genomic segments using RNA-RNA hybrid for nervous necrosis virus (NNV) detection has not been reported yet. The objective of this study was to develop RNA-ISH using RNA probes for the detection of NNV in infects SSN-1 cells or sevenband grouper Hyporthodus septemfasciatus. Two viral RNA segments viz., RNA1 and RNA2 were synthesized by in vitro transcription and labeled with fluorescein UTP and dignoxigenin dUTP, respectively. These labeled RNA probes specifically detected NNV in infected SSN-1 cells. We also applied double labeling RNA-ISH with two-color staining of RNA probes. The results showed that these two viral genomic segments were localized in same regions although RNA1 was also expressed separately. These findings suggest that RNA1 overexpression may be important for sufficient assembly of infectious particles. The RNA-ISH showed that both RNA segments were localized in the tectum opticum, torus semicircualris, cerebellum, thalamus, hypothalamus, and medulla of experimentally infected brain tissues. Especially, RNA segments were highly localized around the ventricle, suggesting that ventricle might play a vital role in the spread of NNV. This technique can be useful for understanding the localization of NNV and the relationship between clinical sign and viral expression.


Subject(s)
Genome, Viral , In Situ Hybridization/methods , Nodaviridae/genetics , RNA Probes/metabolism , Staining and Labeling , Animals , Brain/pathology , Brain/virology , Cell Line , Fishes/virology , Transcription, Genetic
13.
Ann Anat ; 220: 70-78, 2018 Nov.
Article in English | MEDLINE | ID: mdl-30114450

ABSTRACT

In this study, evidence for leptin receptor (LR) and gastric leptin immunoreactivity along the digestive tract of the rainbow trout (Oncorhynchus mykiss), is reported. Besides this, the regulation of gastric leptin and its transcript by fatty acids was analyzed in vitro. LR was detected mainly in the cells of the stomach gastric glands and in the brush border of the epithelium of the anterior, middle and distal intestine. In the stomach LR was co-distributed with leptin. The regulation of gastric leptin and its transcript by fatty acids was analyzed by in vitro incubations. Rabbit polyclonal antibodies anti rainbow trout leptin were developed and employed to detect leptin concentration in the stomach and in the incubation medium. Stomach slices were incubated with butyric (4:0), oleic (18:1n-9), α-linolenic (18:3n-3) and arachidonic fatty acids (20:4n-6). All fatty acids caused an increase in the protein in both the stomach and culture medium, while leptin transcript was not modified. Overall, the results confirm the gastric leptin release upon nutritional modulation.


Subject(s)
Gastrointestinal Tract/metabolism , Leptin/metabolism , Oncorhynchus mykiss/metabolism , Receptors, Leptin/metabolism , Stomach/physiology , Animals , Fatty Acids/metabolism , Female , Gastric Mucosa/metabolism , Gastrointestinal Tract/immunology , Immunohistochemistry , In Vitro Techniques , Leptin/biosynthesis , Male , Proteins/metabolism , Receptors, Leptin/biosynthesis , Receptors, Leptin/immunology , Tissue Distribution
14.
ACS Synth Biol ; 7(2): 405-411, 2018 02 16.
Article in English | MEDLINE | ID: mdl-29370697

ABSTRACT

Single-molecule FRET (smFRET) is a powerful tool to investigate conformational changes of biological molecules. In general, smFRET studies require protein samples that are site-specifically double-labeled with a pair of donor and acceptor fluorophores. The common approaches to produce such samples cannot be applied when studying the synthesis and folding of the polypeptide chain on the ribosome. The best strategy is to incorporate two fluorescent amino acids cotranslationally using cell-free protein synthesis systems. Here, we demonstrate the cotranslational site-specific incorporation into a model protein of Atto633, a dye with excellent photophysical properties, suitable for single molecule spectroscopy, together with a second dye using a combination of the sense cysteine and the nonsense amber codon. In this work we show that cotranslational incorporation of good fluorophores into proteins is a viable strategy to produce suitable samples for smFRET studies.


Subject(s)
Calmodulin , Fluorescence Resonance Energy Transfer , Fluorescent Dyes/chemistry , Protein Engineering/methods , Protein Modification, Translational , Staining and Labeling/methods , Calmodulin/biosynthesis , Calmodulin/chemistry , Calmodulin/genetics , Escherichia coli , Humans
15.
Bio Protoc ; 8(12): e2881, 2018 Jun 20.
Article in English | MEDLINE | ID: mdl-34285993

ABSTRACT

Single-molecule FRET (smFRET) is a powerful tool to investigate molecular structures and conformational changes of biological molecules. The technique requires protein samples that are site-specifically equipped with a pair of donor and acceptor fluorophores. Here, we present a detailed protocol for preparing double-labeled proteins for smFRET studies. The protocol describes two cell-free approaches to achieve a selective label scheme that allows the highest possible accuracy in inter-dye distance determination.

16.
Article in Chinese | WPRIM (Western Pacific) | ID: wpr-733620

ABSTRACT

Objective To investigate the corneal permeability of cyclosprin A (CsA) loaded on polymeric vector after topical application. Methods The grafted copolymer chitosan.graft.cyclodextrin ( CS.g.CD ) was synthesized, and the physicochemical structures of the polymer were investigated using nuclear magnetic resonance spectroscopy ( NMR) and fourier transform infrared spectroscopy ( FT.IR) . A novel CsA eye drop was prepared using the grafted copolymer as carrier material. The physicochemical properties of eye drop,including drug.loading content, osmotic pressure and viscosity were investigated by high performance liquid chromatography.mass spectrometry ( HPLC.MS) ,osmotic pressure gauge and viscometer,respectively. New Zealand albino rabbits were randomly divided into intact cornea CsA group, epithelium debrided CsA group and epithelium debrided control group. The corneal epithelia of the left eyes was debrided in the cornea epithelium debrided group. Cornea irritation test was performed on New Zealand albino rabbits. The aqueous humor was taken and the corneas were collected at 0. 5 hour and 1 hour after instilled. The concentration of CsA was measured by HPLC.MS. Cy5 labeled vector loaded with Coumarin 6 served as model copolymers system, the penetration capabilities of the double fluorescent labeling copolymers system were monitored in vivo using two.photon scanning fluorescence microscopy on murine corneas after topical application. The use and care of the animals complied with Regulations for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission. Results The polymer of CS.g.CD was successfully synthesized and confirmed using NMR and FT.IR. The drug loading of CsA in eye drop solution was 0. 06 %;the osmotic pressure was 305 mOsmol/kg and the viscosity was 36. 5 cP. The CsA drug delivery system had a reversible temperature.sensitive drug release behavior and had no obvious irritation on the eyes of New Zealand rabbits. One hour after treatment,the concentration of CsA in the cornea and aqueous humor of epithelium debrided CsA group was (5. 88±1. 46)μg/g and (149. 19±3. 93)ng/ml,respectively,which was significantly higher than (3. 98±0. 95)μg/g and (30. 25±11. 43)ng/ml in epithelium debrided control group (both at P<0. 05);the concentration of CsA in the aqueous humor of intact cornea CsA group was ( 7. 23 ± 1. 31 ) ng/ml, which was significantly lower than that in epithelium debrided CsA group ( P<0. 05 ) . Polymer vectors were mainly retained in the corneal epithelium, and coumarin 6 gradually diffused into the deep corneal stroma with time. Conclusions The grafted copolymer can load CsA,and the eye drop can effectively overcome the corneal barrier and increase the corneal permeability of CsA.

17.
Neuropeptides ; 65: 45-55, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28460791

ABSTRACT

The superior sagittal sinus (SSS) of the mammalian brain is a pain-sensitive intracranial vessel thought to play a role in the pathogenesis of migraine headaches. Here, we aimed to investigate the presence and the potential co-localization of some neurotransmitters in the human SSS. Immunohistochemical and double-labeling immunofluorescence analyses were applied to paraformaldehyde-fixed, paraffin-embedded, coronal sections of the SSS. Protein extraction and Western blotting technique were performed on the same material to confirm the morphological data. Our results showed nerve fibers clustered mainly in large bundles tracking parallel to the longitudinal axis of the sinus, close in proximity to the vascular endothelium. Smaller fascicles of fibers encircled the vascular lumen in a spiral fashion, extending through the subendothelial connective tissue. Isolated nerve fibers were observed around the openings of bridging veins in the sinus or around small vessels extending into the perisinusal dura. The neurotransmitters calcitonin gene related peptide (CGRP), substance P (SP), neuronal nitric oxide synthase (nNOS), vasoactive intestinal polypeptide (VIP), tyrosine hydroxylase (TH), and neuropeptide Y (NPY) were found in parietal nerve structures, distributed all along the length of the SSS. Overall, CGRP- and TH-containing nerve fibers were the most abundant. Neurotransmitters co-localized in the same fibers in the following pairs: CGRP/SP, CGRP/NOS, CGRP/VIP, and TH/NPY. Western blotting analysis confirmed the presence of such neurosubstances in the SSS wall. Overall our data provide the first evidence of the presence and co-localization of critical neurotransmitters in the SSS of the human brain, thus contributing to a better understanding of the sinus functional role.


Subject(s)
Neuropeptides/metabolism , Superior Sagittal Sinus/cytology , Superior Sagittal Sinus/innervation , Superior Sagittal Sinus/metabolism , Calcitonin Gene-Related Peptide/metabolism , Female , Humans , Male , Neuropeptide Y/metabolism , Neurotransmitter Agents/metabolism , Nitric Oxide Synthase Type I/metabolism , Substance P/metabolism , Tyrosine 3-Monooxygenase/metabolism , Vasoactive Intestinal Peptide/metabolism
18.
J Chem Neuroanat ; 61-62: 83-7, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25128629

ABSTRACT

We have determined whether brain-derived neurotrophic factor immunoreactive (BDNF-ir) neurons in the vagal ganglia innervate the gastrointestinal tract. Many BDNF-ir neurons were medium in size and located throughout the jugular and nodose ganglia. When Fluorogold was injected into the wall of the cervical esophagus, many retrogradely Fluorogold-labeled neurons were found in both the jugular ganglion and the nodose ganglion. When Fluorogold was injected into the body of the stomach or applied to the cut end of the subdiaphragmatic vagus nerve, numerous Fluorogold-labeled neurons were found mostly in the nodose ganglion. Double-labeling combining immunohistochemistry for BDNF and retrograde tracing with Fluorogold showed that more than 90% of the neurons in the jugular ganglion and the nodose ganglion projecting to the cervical esophagus contained BDNF-like immunoreactivity. In the cases of both Fluorogold injection into the stomach and Fluorogold application to the subdiaphragmatic vagus nerve, almost all Fluorogold-labeled neurons in the nodose ganglion contained BDNF-like immunoreactivity. These results indicated that almost all vagal sensory neurons located in either the jugular ganglion or the nodose ganglion that innervate the gastrointestinal tract are BDNF-ir neurons.


Subject(s)
Brain-Derived Neurotrophic Factor/biosynthesis , Gastrointestinal Tract/innervation , Sensory Receptor Cells/cytology , Vagus Nerve/cytology , Animals , Brain-Derived Neurotrophic Factor/analysis , Immunohistochemistry , Male , Rats , Rats, Sprague-Dawley , Sensory Receptor Cells/metabolism , Vagus Nerve/metabolism
19.
Brain Res Bull ; 99: 48-62, 2013 Oct.
Article in English | MEDLINE | ID: mdl-24107244

ABSTRACT

The distribution, colocalization with enzymes producing nitric oxide (NO), and the synaptic organization of neurons containing two calcium-binding proteins (CaBPs) - parvalbumin (Parv) and calbindin-D28K (Calb) - were investigated in the rat periaqueductal gray matter (PAG). Parv-immunopositive (ParvIP) neurons were detected in the mesencephalic nucleus and rarely in the PAG. CalbIP neurons were found both in the dorsolateral (PAG-dl) and ventrolateral PAG (PAG-vl); their size ranged from 112.96 µm(2) (PAG-dl) to 125.13 µm(2) (PAG-vl). Ultrastructurally Parv and Calb immunoreactivity was mostly found in dendritic profiles. Axon terminals containing each of the two CaBPs formed symmetric synapses. Moreover both Parv and Calb were used to label a subpopulation of NO-producing neurons. Colocalization was investigated using two protocols: (i) a combination of Calb and Parv immunocytochemistry (Icc) with nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) histochemistry (Hi) and (ii) neuronal NO synthase-Icc (nNOS) (immunofluorescence). Both techniques demonstrated a complete lack of colocalization of Parv and NADPH-d/nNOS in PAG neurons. Double-labeled (DL) neurons (Calb-NADPH-d; Calb-nNOS) were detected in PAG-dl. NADPH-d-Hi/Calb-Icc indicated that 41-47% of NADPH-d-positive neurons contained Calb, whereas 17-23% of CalbIP cells contained NADPH-d. Two-color immunofluorescence revealed that 53-66% of nNOSIP cells colocalized with Calb and 24-34% of CalbIP neurons contained nNOS. DL neuron size was 104.44 µm(2); neurons labeled only with NADPH-d or Calb measured 89.793 µm(2) and 113.48 µm(2), respectively. Together with previous findings (Barbaresi et al. [2012]) these data suggest that: Therefore the important aspect of the PAG intrinsic organization emerging from this and previous double-labeling studies is the chemical diversity of NO-synthesizing neurons, which is likely related to the different functions in which these neurons are involved.


Subject(s)
Calbindin 1/metabolism , Neurons/metabolism , Nitric Oxide Synthase Type I/metabolism , Parvalbumins/metabolism , Periaqueductal Gray/cytology , Animals , Calbindin 1/ultrastructure , Cell Count , Male , Microscopy, Immunoelectron , NADP/metabolism , NADP/ultrastructure , Neurons/ultrastructure , Nitric Oxide Synthase Type I/ultrastructure , Parvalbumins/ultrastructure , Periaqueductal Gray/metabolism , Rats , Rats, Sprague-Dawley
SELECTION OF CITATIONS
SEARCH DETAIL
...