| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Lv, Yuanyuan, et al.
(författare)
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Angiotensin-Converting Enzyme Gene D/I Polymorphism in Relation to Endothelial Function and Endothelial-Released Factors in Chinese Women
- 2020
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Ingår i: Frontiers in Physiology. - : FRONTIERS MEDIA SA. - 1664-042X. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- Many studies have investigated the relationship between angiotensin-converting enzyme (ACE) D/I polymorphism and cardiovascular disease or endothelial dysfunction; however, hardly any of these studies has taken aging or menopause into consideration. Furthermore, despite that many studies have examined the regulatory effects of endothelial-released factors (ERFs) on endothelial function, no study has evaluated the relationship between ERFs and endothelial function with respect toACED/I polymorphism and menopause status. To answer these questions, 391 healthy Chinese women over a wide range of ages (22-75 years) were enrolled and divided into pre-menopause group and post-menopause group. AfterACED/I genotype being identified, the women were then classified into either DI/II or DD genotype. Flow-mediated dilatation (FMD) of brachial endothelium and plasma levels of ERFs: nitric oxide (NO), endothelin-1 (ET-1), and angiotensin II (Ang II) were measured. The results showed that frequencies ofACED/I genotypes were in accordance with the Hardy-Weinberg equilibrium, and the frequency of I allele was higher than D allele. In pre-menopause group, FMD was significantly higher in women of DI/II than DD (P= 0.032), and age-dependent in both genotypes (DD,P= 0.0472; DI/II,P< 0.0001). In post-menopause group, FMD was similar between women of DI/II and DD, and age-dependent only in women of DI/II (P< 0.0001). In pre-menopause group, Ang II level was significantly higher in women of DD than DI/II (P= 0.029), and FMD was significantly correlated with all ERFs in women of DD (NO,P= 0.032; ET-1,P= 0.017; Ang II,P= 0.002), but only with Ang II in women of DI/II (P= 0.026). In post-menopause group, no significant difference was observed in any ERF between women of DI/II and DD, and FMD was only significantly correlated with ET-1 in women of DD (P= 0.010). In summary, FMD in women of DI/II was superior to DD in pre-menopause and more age-dependent than DD in post-menopause, and FMD was closely associated with ERFs. In conclusion, Chinese women of DI/II seem to have lower risk than DD in pre-menopause, but similar risk as DD in post-menopause in developing cardiovascular disease.
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| 3. |
- Zhuang, Ting, et al.
(författare)
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SHARPIN stabilizes estrogen receptor a and promotes breast cancer cell proliferation
- 2017
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Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 8:44, s. 77137-77151
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Tidskriftsartikel (refereegranskat)abstract
- Estrogen receptor a is expressed in the majority of breast cancers and promotes estrogen-dependent cancer progression. In our study, we identified the novel E3 ubiquitin ligase SHARPIN function to facilitate ERα signaling. SHARPIN is highly expressed in human breast cancer and correlates with ERα protein level by immunohistochemistry. SHARPIN expression level correlates with poor prognosis in ERα positive breast cancer patients. SHARPIN depletion based RNA-sequence data shows that ERα signaling is a potential SHARPIN target. SHARPIN depletion significantly decreases ERα protein level, ERα target genes expression and estrogen response element activity in breast cancer cells, while SHARPIN overexpression could reverse these effects. SHARPIN depletion significantly decreases estrogen stimulated cell proliferation in breast cancer cells, which effect could be further rescued by ERα overexpression. Further mechanistic study reveals that SHARPIN mainly localizes in the cytosol and interacts with ERα both in the cytosol and the nuclear. SHARPIN regulates ERα signaling through protein stability, not through gene expression. SHARPIN stabilizes ERα protein via prohibiting ERα protein poly-ubiquitination. Further study shows that SHARPIN could facilitate the mono-ubiquitinaiton of ERα at K302/303 sites and facilitate ERE luciferase activity. Together, our findings propose a novel ERα modulation mechanism in supporting breast cancer cell growth, in which SHARPIN could be one suitable target for development of novel therapy for ERα positive breast cancer.
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| 4. |
- Chen, Yu, 1990, et al.
(författare)
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Genome-scale modeling for Bacillus coagulans to understand the metabolic characteristics
- 2020
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Ingår i: Biotechnology and Bioengineering. - : Wiley. - 0006-3592 .- 1097-0290. ; 117:11, s. 3545-3558
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Tidskriftsartikel (refereegranskat)abstract
- Lactic acid is widely used in many industries, especially in the production of poly-lactic acid. Bacillus coagulans is a promising lactic acid producer in industrial fermentation due to its thermophilic property. In this study, we developed the first genome-scale metabolic model (GEM) of B. coagulans iBag597, together with an enzyme-constrained model ec-iBag597. We measured strain-specific biomass composition and integrated the data into a biomass equation. Then, we validated iBag597 against experimental data generated in this study, including amino acid requirements and carbon source utilization, showing that simulations were generally consistent with the experimental results. Subsequently, we carried out chemostats to investigate the effects of specific growth rate and culture pH on metabolism of B. coagulans. Meanwhile, we used iBag597 to estimate the intracellular metabolic fluxes for those conditions. The results showed that B. coagulans was capable of generating ATP via multiple pathways, and switched among them in response to various conditions. With ec-iBag597, we estimated the protein cost and protein efficiency for each ATP-producing pathway to investigate the switches. Our models pave the way for systems biology of B. coagulans, and our findings suggest that maintaining a proper growth rate and selecting an optimal pH are beneficial for lactate fermentation.
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| 5. |
- Cheng, Peirui, et al.
(författare)
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Highly Efficient Ruddlesden–Popper Halide Perovskite PA2MA4Pb5I16 Solar Cells
- 2018
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Ingår i: ACS Energy Letters. - : American Chemical Society (ACS). - 2380-8195. ; 3:8, s. 1975-1982
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Tidskriftsartikel (refereegranskat)abstract
- Two-dimensional (2D) Ruddlesden-Popper (RP) organic-inorganic perovskites have emerged as promising candidates for solar cells with technologically relevant stability. Herein, a new RP perovskite, the fifth member («n» = 5) of the (CH3(CH2)2NH3)2(CH3NH3)n-1PbnI3n+1 family (abbreviated as PA2MA4Pb5I16), was synthesized and systematically investigated in terms of photovoltaic application. The obtained pure PA2MA4Pb5I16 crystal exhibits a direct band gap of Eg = 1.85 eV. Systematic analysis on the solid film highlights the key role of the precursor-solvent interaction in the quantum well orientation, phase purity, grain size, surface quality, and optoelectronic properties, which can be well-tuned with addition of dimethyl sulfoxide (DMSO) into the N,N-dimethylformamide (DMF) precursor solution. These findings present opportunities for designing a high-quality RP film with well-controlled quantum well orientation, micrometer-sized grains, and optoelectronic properties. As a result, we achieved power conversion efficiency (PCE) up to 10.41%.
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| 6. |
- Hou, Yuanyuan, et al.
(författare)
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Comparative study of pressure-induced polymerization of C60 nanorods and single crystals
- 2007
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Ingår i: Journal of Physics Condensed Matter. - Bristol : Institute of Physics. - 0953-8984 .- 1361-648X. ; 19:42, s. 425207-
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we report a comparative study of pressure-induced polymerization in C60 nanorods and bulk single crystals, treated simultaneously under various pressures and temperatures in the same experiment. For both materials, orthorhombic, tetragonal and rhombohedral phases have been produced under high pressure and high temperature. The structures have been identified and compared between the two sample types by Raman and photoluminescence spectroscopy. There are differences between the Raman and photoluminescence spectra from the two types of materials for all polymeric phases, but especially for the tetragonal phase. From the comparison between nanorods and bulk samples, we tentatively assign photoluminescence peaks for various polymeric phases.
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| 7. |
- Hou, Yuanyuan, et al.
(författare)
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Photoluminescence properties of high-pressure-polymerized C60 nanorods in the orthorhombic and tetragonal phases.
- 2006
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 89:18, s. 181925-
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Tidskriftsartikel (refereegranskat)abstract
- C60nanorods in two polymeric phases have been synthesized under differenthigh pressure and high temperature conditions. Orthorhombic and tetragonal phaseshave been identified from Raman spectra. The rod shape canbe kept under quasihydrostatic pressure. The photoluminescence intensity of thepolymeric C60 nanorods has been greatly enhanced compared with thatof pristine C60 nanorods. The main fluorescence band shifted from730 nm in the unpolymeric phase to 748 nm and near infrared780 nm in the orthorhombic and tetragonal phases, respectively. The enhancedphotoluminescence with tunable frequency for different polymeric C60 nanorods suggestspotential applications in luminescent nanomaterials.
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| 8. |
- Hou, Yuanyuan, et al.
(författare)
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Pressure-induced polymerization of nano- and submicrometer C60 rods into a rhombohedral phase
- 2006
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Ingår i: Chemical Physics Letters. - : Elsevier BV. - 0009-2614. ; 423:1-3, s. 215-219
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Tidskriftsartikel (refereegranskat)abstract
- C-60 rods with nano- and submicrometer dimensions were polymerized at 4.5 GPa and 973 K. Raman spectroscopy showed that the material transformed into a rhombohedral polymeric structure under high pressure and high temperature (HPHT) conditions. The HPHT polymerized samples keep the original rod shape. The position dependence of photoluminescence (PL) spectra have been studied on the rhombohedral polymer C60 rods at room temperature. The intensity of the 1.74 eV peak from the rhombohedral phase varies systematically between the edge of and the middle of the rod. Our results indicate that the 1.74 eV peak originates from surface defects.
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| 9. |
- Li, Yuanyuan, et al.
(författare)
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Cellulose nanofibers enable paraffin encapsulation and the formation of stable thermal regulation nanocomposites
- 2017
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Ingår i: Nano Energy. - : Elsevier BV. - 2211-2855. ; 34, s. 541-548
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Tidskriftsartikel (refereegranskat)abstract
- Non-leaking, green materials with high content of phase change materials (PCM) can conserve solar energy and contribute to a sustainable society. Here, paraffin was encapsulated by nanocellulose (CNF) through a pickering emulsion method, while simultaneously forming a composite material. The thermodynamic drive for phase separation was confirmed by molecular modeling. Particle formation was characterized by dynamic light scattering and they were processed into stable PCM/CNF composites in the form of PCM paper structures with favorable mechanical properties. The PCM composite was lightweight and showed a solid content of paraffin of more than 72 wt%. Morphology was characterized using FE-SEM. The thermal regulation function of the PCM composite was demonstrated in the form of a model roof under simulated sunlight. No obvious leakage was observed during heating/cooling cycles, as supported by DSC and SAXS data. The PCM composite can be extended to panels used in energy-efficient smart buildings with thermal regulation integrated in load-bearing structures.
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| 10. |
- Li, Ya, et al.
(författare)
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Click chemistry-based biopolymeric hydrogels for regenerative medicine
- 2021
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Ingår i: Biomedical Materials. - : Institute of Physics Publishing (IOPP). - 1748-6041 .- 1748-605X. ; 16:2
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Forskningsöversikt (refereegranskat)abstract
- Click chemistry is not a single specific reaction, but describes ways of generating products which emulate examples in nature. Click reactions occur in one pot, are not disturbed by water, generate minimal and inoffensive byproducts, and are characterized by a high thermodynamic driving force, driving the reaction quickly and irreversibly towards a high yield of a single reaction product. As a result, over the past 15 years it has become a very useful bio-orthogonal method for the preparation of chemical cross-linked biopolymer-based hydrogel, in the presence of e.g. growth factors and live cells, or in-vivo. Biopolymers are renewable and non-toxic, providing a myriad of potential backbone toolboxes for hydrogel design. The goal of this review is to summarize recent advances in the development of click chemistry-based biopolymeric hydrogels, and their applications in regenerative medicine. In particular, various click chemistry approaches, including copper-catalyzed azide-alkyne cycloaddition reactions, copper-free click reactions (e.g. the Diels-Alder reactions, the strain-promoted azide-alkyne cycloaddition reactions, the radical mediated thiol-ene reactions, and the oxime-forming reactions), and pseudo-click reactions (e.g. the thiol-Michael addition reactions and the Schiff base reactions) are highlighted in the first section. In addition, numerous biopolymers, including proteins (e.g. collagen, gelatin, silk, and mucin), polysaccharides (e.g. hyaluronic acid, alginate, dextran, and chitosan) and polynucleotides (e.g. deoxyribonucleic acid), are discussed. Finally, we discuss biopolymeric hydrogels, cross-linked by click chemistry, intended for the regeneration of skin, bone, spinal cord, cartilage, and cornea. This article provides new insights for readers in terms of the design of regenerative medicine, and the use of biopolymeric hydrogels based on click chemistry reactions.
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