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Search results for: Biotin

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#32473152   2020/05/27 To Up

Prevalence of detectable biotin in The Netherlands in relation to risk on immunoassay interference.

Despite the increasing awareness about biotin interference with immunoassays, so far, only two studies have quantified the prevalence of elevated biotin in patient populations. In a US study, over 7% had biotin concentrations exceeding 10 ng/mL, whereas in an Australian study only 0.8% of ED samples contained biotin exceeding 10 ng/mL. At present, representative data for the European population are lacking. In this study, we investigated biotin prevalence in The Netherlands in a representative cohort of routine laboratory requests in our laboratory using an LC-MS/MS assay for quantification of biotin in human plasma. In our study, we found 0.2% of samples exceeding 10 ng/mL of biotin, a finding more or less in line with the Australian data. Even though the biotin prevalence appears to be low, with concomitant low to moderate biotin concentrations, it is by no means a rare phenomenon. Laboratories like ours are likely to experience biotin positive samples on a daily basis with variable impact on patient care depending on the analytical bias from the immunoassay platform used. Our simple and robust LC-MS/MS assay for quantification of biotin in human samples may contribute to better understanding of the systemic concentrations seen after moderate- and high-dose biotin supplementation and the extent of immunoassay interference.
A IJpelaar, A Beijers, H van Daal, J M W van den Ouweland

2637 related Products with: Prevalence of detectable biotin in The Netherlands in relation to risk on immunoassay interference.

1100 μg1001 kit1 mg100ug500 gm.

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#32470346   2020/05/26 To Up

Background-free cell surface glycan analysis using persistent luminescence nanoparticle as an optical probe.

In this work, we report a novel cell surface glycan analysis method based on persistent luminescence nanoparticle (PLNP) ZnGaO: Cr (ZGC) as an optical probe. ZGC was first silanized by (3-Aminopropyl) triethoxysilane (APTES), followed by PEGylation with NHS-P EG-Biotin, which not only introduces biotin, but significantly improves the dispersibility and stability of the nanoparticles. Neutral-avidin was then coupled on ZGC surface through the specific biotin-avidin interaction, producing a ZGC-PEG-avidin nanoprobe. As for cell surface glycan detection, different surface glycans are recognized with their corresponding biotinylated lectins, which are then traced by ZGC-PEG-avidin. The persistent luminescence signal is recorded by a microtiter plate reader in time-resolved fluorescence mode. Glycans expression profiling on prostate cancer cell DU145 and normal prostate cell RWPE-1 was analyzed by the proposed detection platform. Similar results were observed from the conventional horseradish peroxidase (HRP)-catalyzed absorbent assay and confocal microscope-based fluorescence imaging, demonstrating the applicability of the proposed platform. The approach based on the long afterglow property of ZGC efficiently eliminates the background noise from cells and substrate, resulting in the best signal-to-noise ratio and high detection sensitivity.
Na He, Ying Jiang, Lingli Lei, Yingshuai Liu

2317 related Products with: Background-free cell surface glycan analysis using persistent luminescence nanoparticle as an optical probe.

0.5 ml1 kit1 kit1 kit1 kit96 tests1 kit1 kit1 kit

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#32470320   2020/05/22 To Up

A Clickable APEX Probe for Proximity-Dependent Proteomic Profiling in Yeast.

The engineered ascorbate peroxidase (APEX) is a powerful tool for the proximity-dependent labeling of proteins and RNAs in live cells. Although widely use in mammalian cells, APEX applications in microorganisms have been hampered by the poor labeling efficiency of its biotin-phenol (BP) substrate. In this study, we sought to address this challenge by designing and screening a panel of alkyne-functionalized substrates. Our best probe, Alk-Ph, substantially improves APEX-labeling efficiency in intact yeast cells, as it is more cell wall-permeant than BP. Through a combination of protein-centric and peptide-centric chemoproteomic experiments, we have identified 165 proteins with a specificity of 94% in the yeast mitochondrial matrix. In addition, we have demonstrated that Alk-Ph is useful for proximity-dependent RNA labeling in yeast, thus expanding the scope of APEX-seq. We envision that this improved APEX-labeling strategy would set the stage for the large-scale mapping of spatial proteome and transcriptome in yeast.
Yi Li, Caiping Tian, Keke Liu, Ying Zhou, Jing Yang, Peng Zou

1228 related Products with: A Clickable APEX Probe for Proximity-Dependent Proteomic Profiling in Yeast.

252ug4 Membranes/Box200 96T10 mg

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#32470050   2020/05/29 To Up

Pyrrolocin C and equisetin inhibit bacterial acetyl-CoA carboxylase.

Antimicrobial resistance is a growing global health and economic concern. Current antimicrobial agents are becoming less effective against common bacterial infections. We previously identified pyrrolocins A and C, which showed activity against a variety of Gram-positive bacteria. Structurally similar compounds, known as pyrrolidinediones (e.g., TA-289, equisetin), also display antibacterial activity. However, the mechanism of action of these compounds against bacteria was undetermined. Here, we show that pyrrolocin C and equisetin inhibit bacterial acetyl-CoA carboxylase (ACC), the first step in fatty acid synthesis. We used transcriptomic data, metabolomic analysis, fatty acid rescue and acetate incorporation experiments to show that a major mechanism of action of the pyrrolidinediones is inhibition of fatty acid biosynthesis, identifying ACC as the probable molecular target. This hypothesis was further supported using purified proteins, demonstrating that biotin carboxylase is the inhibited component of ACC. There are few known antibiotics that target this pathway and, therefore, we believe that these compounds may provide the basis for alternatives to current antimicrobial therapy.
Erica C Larson, Albebson L Lim, Christopher D Pond, Matthew Craft, Mirela Čavužić, Grover L Waldrop, Eric W Schmidt, Louis R Barrows

1871 related Products with: Pyrrolocin C and equisetin inhibit bacterial acetyl-CoA carboxylase.

25 mg100 mg25 mg10 mg50ul10 mg50ul25 mg25 mg2.5 mg5 mg

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#32470040   2020/05/29 To Up

Effects of Biotin on survival, ensheathment, and ATP production by oligodendrocyte lineage cells in vitro.

Mechanisms implicated in disease progression in multiple sclerosis include continued oligodendrocyte (OL)/myelin injury and failure of myelin repair. Underlying causes include metabolic stress with resultant energy deficiency. Biotin is a cofactor for carboxylases involved in ATP production that impact myelin production by promoting fatty acid synthesis. Here, we investigate the effects of high dose Biotin (MD1003) on the functional properties of post-natal rat derived oligodendrocyte progenitor cells (OPCs). A2B5 positive OPCs were assessed using an in vitro injury assay, culturing cells in either DFM (DMEM/F12+N1) or "stress media" (no glucose (NG)-DMEM), with Biotin added over a range from 2.5 to 250 μg/ml, and cell viability determined after 24 hrs. Biotin reduced the increase in OPC cell death in the NG condition. In nanofiber myelination assays, biotin increased the percentage of ensheathing cells, the number of ensheathed segments per cell, and length of ensheathed segments. In dispersed cell culture, Biotin also significantly increased ATP production, assessed using a Seahorse bio-analyzer. For most assays, the positive effects of Biotin were observed at the higher end of the dose-response analysis. We conclude that Biotin, in vitro, protects OL lineage cells from metabolic injury, enhances myelin-like ensheathment, and is associated with increased ATP production.
Qiao-Ling Cui, Yun Hsuan Lin, Yu Kang T Xu, Milton G F Fernandes, Vijayaraghava T S Rao, Timothy E Kennedy, Jack Antel

2574 related Products with: Effects of Biotin on survival, ensheathment, and ATP production by oligodendrocyte lineage cells in vitro.

10 ug100 µg1x10e7 cells96 tests100ug1.00 flask100ug100ug100ug1 mg1x10e7 cells

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#32467232   2020/05/28 To Up

Role for carbohydrate response element-binding protein (ChREBP) in high glucose-mediated repression of long noncoding RNA Tug1.

Long-noncoding RNAs (lncRNAs) have been shown to play key roles in a variety of biological activities of the cell. However, less is known about how lncRNAs respond to environmental cues, and what transcriptional mechanisms regulate their expression. Studies from our laboratory have shown that the lncRNA Tug1 (taurine upregulated gene 1) is crucial for progression of diabetic kidney disease, a major microvascular complication of diabetes. Using a combination of proximity labeling with the engineered soybean ascorbate peroxidase (APEX2), ChIP-qPCR, biotin-labeled oligo-nucleotides pulldown, and classical promoter luciferase assays in kidney podocytes, we extend our initial observations in the current study, and now provide a detailed analysis on how high glucose milieu down-regulates Tug1 expression in podocytes. Our results revealed an essential role for the transcription factor carbohydrate response element binding protein (ChREBP) in controlling Tug1 transcription in the podocytes in response to increased glucose levels.  Along with ChREBP, other co-regulators, including MAX dimerization protein (MLX), MAX dimerization protein 1 (MXD1), and histone deacetylase 1 (HDAC1) were enriched at the Tug1 promoter under the high-glucose conditions. These observations provide the first characterization of the mouse Tug1 promoter's response to the high glucose milieu. Our findings illustrate a molecular mechanism by which ChREBP can coordinate glucose homeostasis with the expression of the lncRNA Tug1, and further our understanding of dynamic transcriptional regulation of lncRNAs in a disease state.
Jianyin Long, Daniel L Galvan, Koki Mise, Yashpal S Kanwar, Li Li, Naravat Poungvarin, Paul A Overbeek, Benny H Chang, Farhad R Danesh

2333 related Products with: Role for carbohydrate response element-binding protein (ChREBP) in high glucose-mediated repression of long noncoding RNA Tug1.

100.00 ug96tests100.00 ug 100 UG2 Pieces/Box100.00 ug100μg 100 UG100.00 ug100.00 ug100 μg2 Pieces/Box

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#32467229   2020/05/27 To Up

The BADC and BCCP subunits of chloroplast acetyl-CoA carboxylase sense the pH changes of the light-dark cycle.

Acetyl-CoA carboxylase (ACCase) catalyzes the first committed step in synthesis of fatty acids. The multisubunit ACCase in the chloroplast is activated by a shift to pH 8 upon light adaptation and is inhibited by a shift to pH 7 upon dark adaptation. Here, titrations with the purified ACCase BADC and BCCP subunits from Arabidopsis indicated that they can competently and independently bind biotin carboxylase (BC), but differ in responses to pH changes representing those in the plastid stroma during light or dark conditions. At pH 7 in phosphate buffer, BADC1 and BADC2 gain an advantage over BCCP1 and BCCP2 in affinity for BC. At pH 8 in KCl solution, however, BCCP1 and BCCP2 had more than 10-fold higher affinity for BC than did BADC1. The pH-modulated shifts in BC preferences for BCCP and BADC partners suggest they contribute to light-dependent regulation of heteromeric ACCase. Using NMR spectroscopy, we found evidence for increased intrinsic disorder of the BADC and BCCPs subunits at pH 7. We propose that this intrinsic disorder potentially promotes fast association with BC through a "fly-casting mechanism." We hypothesize that the pH effects on the BADC and BCCP subunits attenuate ACCase activity by night and enhance it by day. Consistent with this hypothesis, Arabidopsis mutant lines grown in a light-dark cycle synthesized more fatty acids in their seeds. In summary, our findings provide evidence that the BADC and BCCP subunits function as pH sensors required for light-dependent switching of heteromeric ACCase activity.
Yajin Ye, Yan G Fulcher, David J Sliman, Mizani T Day, Mark J Schroeder, Rama K Koppisetti, Philip D Bates, Jay J Thelen, Steven R Van Doren

2028 related Products with: The BADC and BCCP subunits of chloroplast acetyl-CoA carboxylase sense the pH changes of the light-dark cycle.

100 U100.00 ul1200 units100 500IUmin 2 cartons

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#32466521   2020/05/26 To Up

Multifunctional and Transformable 'Clickable' Hydrogel Coatings on Titanium Surfaces: From Protein Immobilization to Cellular Attachment.

Multifunctionalizable hydrogel coatings on titanium interfaces are useful in a wide range of biomedical applications utilizing titanium-based materials. In this study, furan-protected maleimide groups containing multi-clickable biocompatible hydrogel layers are fabricated on a titanium surface. Upon thermal treatment, the masked maleimide groups within the hydrogel are converted to thiol-reactive maleimide groups. The thiol-reactive maleimide group allows facile functionalization of these hydrogels through the thiol-maleimide nucleophilic addition and Diels-Alder cycloaddition reactions, under mild conditions. Additionally, the strained alkene unit in the furan-protected maleimide moiety undergoes radical thiol-ene reaction, as well as the inverse-electron-demand Diels-Alder reaction with tetrazine containing molecules. Taking advantage of photo-initiated thiol-ene 'click' reactions, we demonstrate spatially controlled immobilization of the fluorescent dye thiol-containing boron dipyrromethene (BODIPY-SH). Lastly, we establish that the extent of functionalization on hydrogels can be controlled by attachment of biotin-benzyl-tetrazine, followed by immobilization of TRITC-labelled ExtrAvidin. Being versatile and practical, we believe that the described multifunctional and transformable 'clickable' hydrogels on titanium-based substrates described here can find applications in areas involving modification of the interface with bioactive entities.
Tugce Nihal Gevrek, Aysun Degirmenci, Rana Sanyal, Amitav Sanyal

2587 related Products with: Multifunctional and Transformable 'Clickable' Hydrogel Coatings on Titanium Surfaces: From Protein Immobilization to Cellular Attachment.

1mg0.5mg1 kit(96 Wells)20100 0.5mg1 mg51mg1000 TESTS/0.65ml1 mg480/kit

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#32466220   2020/05/25 To Up

Streptavidin-Hosted Organocatalytic Aldol Addition.

In this report, the streptavidin-biotin technology was applied to enable organocatalytic aldol addition. By attaching pyrrolidine to the valeric motif of biotin and introducing it to streptavidin (Sav), a protein-based organocatalytic system was created, and the aldol addition of acetone with -nitrobenzaldehyde was tested. The conversion of substrate to product can be as high as 93%. Although the observed enantioselectivity was only moderate (33:67 er), further protein engineering efforts can be included to improve the selectivity. These results have proven the concept that Sav can be used to host stereoselective aldol addition.
Nicolò Santi, Louis C Morrill, Louis Y P Luk

2939 related Products with: Streptavidin-Hosted Organocatalytic Aldol Addition.

100 μg200 ug100ug Lyophilized25 100 ug200 ug100ul20100ug Lyophilized100 ug10 mL at 10 mg/mL

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#32463398   2020/05/28 To Up

DNA-Programmed plasmonic ELISA for the ultrasensitive detection of protein biomarkers.

We report a novel DNA-programmed plasmonic enzyme-linked immunosorbent assay (ELISA) for the ultrasensitive detection of protein biomarkers with the naked eye. The DNA-programmed plasmonic assay was based on two enzyme-free and isothermal nucleic acid amplification methods: hybridization chain reaction (HCR) and catalyzed hairpin assembly (CHA). In this study, a biotin-labeled DNA probe was utilized insteand of an enzyme-label probe in well-developed ELISA method. The biotin-labeled DNA probe was able to trigger the HCR and CHA processes, and the products could hybridize with DNA-modified gold nanoparticles (AuNPs) to induce the aggregation of the AuNPs and a color change in the solution. The developed method was able to detect as low as 1 pg mL-1 PSA target with the naked eye. Clinical serum samples demonstrated satisfactory results, indicating that the method is useful for early diagnostics and monitoring curative effects after a medical treatment. The developed method presents a simple and portable platform for ultrasensitive protein detection and has potential for point-of-care (POC) diagnostics in less developed areas.
Yu-Hong Cheng, Hao Tang, Ru-Qin Yu, Jian-Hui Jiang

1522 related Products with: DNA-Programmed plasmonic ELISA for the ultrasensitive detection of protein biomarkers.

96 tests1 Kit 96T96T96 wells (1 kit)96T1 mg100ug1 kit(96 Wells)

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