Two-Photon Excitation Spectra of Various Fluorescent Proteins within a Broad Excitation Range.

Two-photon excitation fluorescence laser-scanning microscopy is the preferred method for studying dynamic processes in living organ models or even in living organisms. Thanks to near-infrared and infrared excitation, it is possible to penetrate deep into the tissue, reaching areas of interest relevant to life sciences and biomedicine. In those imaging experiments, two-photon excitation spectra are needed to select the optimal laser wavelength to excite as many fluorophores as possible simultaneously in the sample under consideration. The more fluorophores that can be excited, and the more cell populations that can be studied, the better access to their arrangement and interaction can be reached in complex systems such as immunological organs. However, for many fluorophores, the two-photon excitation properties are poorly predicted from the single-photon spectra and are not yet available, in the literature or databases. Here, we present the broad excitation range (760 nm to 1300 nm) of photon-flux-normalized two-photon spectra of several fluorescent proteins in their cellular environment. This includes the following fluorescent proteins spanning from the cyan to the infrared part of the spectrum: mCerulean3, mTurquoise2, mT-Sapphire, Clover, mKusabiraOrange2, mOrange2, LSS-mOrange, mRuby2, mBeRFP, mCardinal, iRFP670, NirFP, and iRFP720.

Tocotrienols: Exciting Biological and Pharmacological Properties of Tocotrienols and other Naturally Occurring Compounds, Part I.

Inflammation has been implicated in cardiovascular disease and tocotrienols are potent hypocholesterolemic agents that reduce ß-hydroxy-ß-methyl-glutaryl coenzyme A reductase activity, which is degraded via the ubiquitin-proteasome pathway. Impact of various tocotrienols (α-, γ-, or δ-tocotrienol) treatments inhibit the chymotrypsin-like activity of 20S rabbit muscle proteasome (>50%) in RAW 264.7 cells and BALB/c mice. Moreover, the effect of various tocotrienols (α-, γ-, or δ-tocotrienol), α-tocopherol, quercetin, riboflavin, (-) Corey lactone, amiloride, dexamethasone supplemented diets fed to chickens (4-weeks) resulted in reduction of total cholesterol, LDL-cholesterol, and triglycerides. This trend was also observed in macrophages from RAW 264.7 cells, in LPS-induced thioglycolate-elicited peritoneal macrophages derived from C57BL/6, BALB/c, LMP7/MECL-1-/-, and PPAR-α-/- knockout mice from young (4-week-old) and senescent (42-week-old) mice, resulting in significant inhibition of TNF-α and nitric oxide levels (30% to 70%), blocked degradation of P-IκB protein, and decreased activation of NF-κB, followed gene suppression of mRNA levels of TNF-α, IL-1ß, IL-6, and iNOS. In human study, normal or hypercholesterolemic subjects administered two capsules/d of NS-7 or NS-6 (4-weeks) showed decrease in serum CRP, NO, γ-GT, total cholesterol, LDL-cholesterol, and triglycerides levels in normal as compared to hypercholesterolemic subjects (12% to 39%). In second study, hypercholesterolemic subjects were given increasing doses of δ-tocotrienol (125 mg, 250 mg, 500 mg, and 750 mg/day) plus AHA Step-1 diet (4-weeks). The most effective dose of tocotrienols (250 mg/day) may be used to lower serum NO (40%), CRP (40%), MDA (34%), γ-GT (22 %), and inflammatory cytokines IL-1α, IL-12, IFN-γ by 15% to 17%, and increase TAS levels by 22%.

The effect of Malus doumeri leaf flavonoids on oxidative stress injury induced by hydrogen peroxide (H2O2) in human embryonic kidney 293 T cells.

BACKGROUND: In this study, Malus doumeri leaf flavonoids (MDLF) were used as the research object to observe their in vitro antioxidant stress ability. Hydrogen peroxide (H2O2) was used to induce oxidative stress in 293 T cells. METHODS: MTT, flow cytometry, and qPCR were used to verify the effect of MDLF. RESULTS: In vitro cell experiments showed that at a concentration of 0-160 µg/mL, MDLF did not affect the normal proliferation of human embryonic kidney 293 T cells (HEK 293 T cells), and MDLF had no cytotoxic effect in this concentration range. It was found that MDLF could maintain the survival of HEK 293 T cells (82.6%) at a high concentration (160 µg/mL). Morphological observation also found that MDLF can inhibit the cell structure imperfection caused by H2O2. It was also observed that MDLF could significantly increase the levels of catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), and glutathione peroxidase (GSH-Px) and reduce the level of malondialdehyde (MDA). The results of quantitative polymerase chain reaction (qPCR) showed that MDLF could significantly up-regulate the mRNA expression levels of CAT, SOD, GSH, GSH-Px, B-cell lymphoma-2 (Bcl-2) and downregulate the expression levels of B-cell lymphoma-2 associated x protein (Bax), tumor necrosis factor-alpha (TNF-α), and nuclear factor kappa-B (NF-κB) in oxidative stress-injured cells. The HPLC analysis showed that MDLF contained hyperin, isoquercetin, quercitrin, hesperidin, myricetin, baicalin and quercetin. CONCLUSION: From the experimental results, it was observed that MDLF has a strong anti-oxidation ability in vitro, and it can interfere with the oxidative stress damage caused by H2O2 in 293 T cells. Therefore, MDLF is a type of natural substance with good anti-oxidant effect, and it has the potential to interfere with many diseases.

Amplification of human IgG Fc gene and its secretory expression in eukaryotic cells / 中国免疫学杂志

Objective:The immunogenicity of DNA vaccine immunogenicity can be improved by fusing antigenic genes to IgG Fc fragment.It is critical for enhancing immunogenicity of DNA vaccine to construct the secreting eukaryotic expressing vector.The purpose of this study is to construct a secreting eukaryotic expressing vector ligated with IgG Fc gene by amplifying human IgG Fc fragment and fusing the fragment with human CD5 signal peptide sequence for highly efficient expression.Methods:Human lymphocytes were isolated from the tonsil obtained by removal surgery.The total RNA of lymphocytes was extracted using Trizol reagent.Human IgG Fc cDNA was amplified by RT-PCR from lymphocytes and then inserted into pMD-18T vector.The Fc encoding sequence fused with CD5 signal peptide(sp) sequence was constructed by cross PCR using Fc fragment and CD5sp sequence and cloned in pcDNA-CD5 plasmid as the template.CD5sp-Fc fragment was inserted into pcDNA3.1 expressing vector to construct the pcDNA-CD5sp-Fc plasmid.The plasmids were transfected into HEK293T cells mediated by calcium phosphate.Western blot was used to detect expressed Fc protein in cultural supermatant of the cells.Results:The amplified sequence of human IgG Fc was consistent with that previously published.The secretory expression of Fc in HEK293T cells was achieved and the expressing level reached 50 ?g/106 cells at 48 h culture after transfection.Conclusion:The human IgG Fc gene is amplified by RT-PCR methods and the secretory expression of Fc gene mediated by CD5 signal peptide in 293T cells is achieved.The results provide a experimental basis for further construction of antigen genes fused to IgG Fc fragment and investigation on DNA vaccines and Fc as a biological adjuvant.