Imaging of intracellular acidic compartments with a sensitive rhodamine based fluorogenic pH sensor

The parameters of intracellular acidic compartments are altered in apoptosis, autophagy, cancer metastasis, etc. Low background and selective staining of lysosomes and autophagosomes was achieved with N-(rhodamine 6G)-lactam-ethylenediamine (R6G-EDA) which fluoresces in acidic vesicles via pH mediated ring opening of the intramolecular lactam. Long retention time of R6G-EDA in lysosomes and its exceptional stability against photo-bleaching allow full time tracking of lysosome morphology changes in tumor necrosis factor-alpha (TNF-alpha) triggered cell death, suggesting its utility for acidic vesicle studies in cell biology.NSF China[20802060, 21072162, 30830092, 30921005, 91029304, 81061160512]; Xiamen University[2011121020]; 973 program[2009CB522200

Simple filter microchip for rapid separation of plasma and viruses from whole blood

Sample preparation is a significant challenge for detection and sensing technologies, since the presence of blood cells can interfere with the accuracy and reliability of virus detection at the nanoscale for point-of-care testing. To the best of our knowledge, there is not an existing on-chip virus isolation technology that does not use complex fluidic pumps. Here, we presented a lab-on-a-chip filter device to isolate plasma and viruses from unprocessed whole blood based on size exclusion without using a micropump. We demonstrated that viruses (eg, HIV) can be separated on a filter-based chip (2-μm pore size) from HIV-spiked whole blood at high recovery efficiencies of 89.9% ± 5.0%, 80.5% ± 4.3%, and 78.2% ± 3.8%, for viral loads of 1000, 10,000 and 100,000 copies/mL, respectively. Meanwhile, 81.7% ± 6.7% of red blood cells and 89.5% ± 2.4% of white blood cells were retained on 2 μm pore–sized filter microchips. We also tested these filter microchips with seven HIV-infected patient samples and observed recovery efficiencies ranging from 73.1% ± 8.3% to 82.5% ± 4.1%. These results are first steps towards developing disposable point-of-care diagnostics and monitoring devices for resource-constrained settings, as well as hospital and primary care settings

Dual colored mesoporous silica nanoparticles with pH activable rhodamine-lactam for ratiometric sensing of lysosomal acidity

Alteration of lysosome acidity has been implicated in many biological events ranging from apoptosis to cancer metastasis, etc. Mesoporous silica nanoparticles doped with acid activable rhodamine-lactam and fluorescein isothiocyanate (FITC) were developed for ratiometric sensing of lysosomal pH changes in live cells with flow cytometry.NSF China[20802060, 21072162, 30830092, 30921005, 91029304, 81061160512]; Fundamental Research Funds for the Central Universities[2011121020]; 973 program[2009CB522200

A photothermal cell viability-reporting theranostic nanoprobe for intraoperative optical ablation and tracking of tumors

973 program [2013CB93390]; NSFC [21272196, 81071182]; Fundamental Research Funds for the Central Universities [2012121018]; NSF of Fujian Province [2011J06004]; PCSIR; Medical Innovation Foundation of Fujian [2009-CXB-46]A photothermal pH-reporting nanoprobe was developed for intraoperative tumor detection by "turn-on'' fluorescence of the probe inside viable tumor cells, photothermal tumor therapy, and in situ monitoring of tumor killing by non-fluorescence of the probe in damaged cells

Nitrogen addition impacts on the emissions of greenhouse gases depending on the forest type : a case study in Changbai Mountain, Northeast China

Purpose Anthropogenic-induced greenhouse gas (GHG) emission rates derived from the soil are influenced by long-term nitrogen (N) deposition and N fertilization. However, our understanding of the interplay between increased N load and GHG emissions among soil aggregates is incomplete. Materials and methods Here, we conducted an incubation experiment to explore the effects of soil aggregate size and N addition on GHG emissions. The soil aggregate samples (0-10 cm) were collected from two 6-year N addition experiment sites with different vegetation types (mixed Korean pine forest vs. broad-leaved forest) in Northeast China. Carbon dioxide (CO2), nitrous oxide (N2O), and methane (CH4) production were quantified from the soil samples in the laboratory using gas chromatography with 24-h intervals during the incubation (at 20 degrees C for 168 h with 80 % field water capacity). Results and discussion The results showed that the GHG emission/uptake rates were significantly higher in the micro-aggregates than in the macro-aggregates due to the higher concentration of soil bio-chemical properties (DOC, MBC, NO3-, NH4+, SOC and TN) in smaller aggregates. For the N addition treatments, the emission/uptake rates of GHG decreased after N addition across aggregate sizes especially in mixed Korean pine forest where CO2 emission was decreased about 30 %. Similar patterns in GHG emission/uptake rates expressed by per soil organic matter basis were observed in response to N addition treatments, indicating that N addition might decrease the decomposability of SOM in mixed Korean pine forest. The global warming potential (GWP) which was mainly contributed by CO2 emission (>98 %) decreased in mixed Korean pine forest after N addition but no changes in broad-leaved forest. Conclusions These findings suggest that soil aggregate size is an important factor controlling GHG emissions through mediating the content of substrate resources in temperate forest ecosystems. The inhibitory effect of N addition on the GHG emission/uptake rates depends on the forest type.Peer reviewe

Characterization of the response of IHEP-IME LGAD with shallow carbon to Gamma Irradiation

Low Gain Avalanche Detectors (LGAD), as part of High-Granularity Timing Detector (HGTD), is crucial to reducing pileup in the upgrading to HL-LHC. Many studies have been done on the bulk damages of the LGAD. However, there's no study about the surface radiation hardness of the LGAD sensors with carbon implanted. The IHEP-IME LGAD version 3 with the shallow carbon and different interpad separations were irradiated up to 2 MGy by gamma irradiation. The performance of the IHEP-IME LGAD version 3 before and after irradiation had been tested, such as the leakage current, break-down voltage, capacitance, V$_{gl}$, and inter-pad resistance. The results showed that apart from minor fluctuations in some samples, no significant changes concerning inter-pad separation were observed before and after irradiation. Leakage current and break-down voltage increase after irradiation, which is considered due to surface passivation; the overall inter-pad resistance are larger than $10^9\ \Omega$before and after irradiation; capacitance is found to be less than 4.5 pF with a slight drop in V$_{gl}$ after irradiation. All parameters meet the requirements of HGTD, and the results indicated that IHEP-IME LGAD v3 has excellent anti-irradiation performance

A targetable nanogenerator of nitric oxide for light-triggered cytotoxicity

NSF China [21305116, 21272196, 21072162]; 973 program [2013CB933901]; PCSIRT; NFFTBS [J1310024]; Fundamental Research Funds for the Central Universities [2011121020]Nanoscale-vesicles that can target pathogens are valuable for biomedical applications. In this study, a photo-responsive nanogenerator of nitric oxide (NO) comprised of a hydrophobic core of 3trifluoromethyl- 4-nitroaniline (TFNA) and a hydrophilic shell of mannosylated poly[styrene-alter-(maleic acid)] was constructed to target and kill lectin-expressing cells. The release of NO from the nanogenerator (T@ P-M) was effectively induced by luminol-derived chemiluminescence (CL), leading to high-efficiency killing of Escherichia coli (E. coli) treated with T@ P-M. In addition, the uptake of T@ P-M by Raw 264.7 macrophages was achieved by cell surface lectin-mediated endocytosis, enabling the intracellular release of NO from the internalized T@ P-M upon the induction of extracellular chemiluminescence. Because in vivo-generated CL can overcome the limited penetration of exogenous light into biological tissues, T@ P-M has potential uses as a targetable photo-activatable microbicide to combat pathogens bearing lectins or residing in macrophages

BolA-like protein (IbaG) promotes biofilm formation and pathogenicity of Vibrio parahaemolyticus

Vibrio parahaemolyticus is a gram-negative halophilic bacterium widespread in temperate and tropical coastal waters; it is considered to be the most frequent cause of Vibrio-associated gastroenteritis in many countries. BolA-like proteins, which reportedly affect various growth and metabolic processes including flagellar synthesis in bacteria, are widely conserved from prokaryotes to eukaryotes. However, the effects exerted by BolA-like proteins on V. parahaemolyticus remain unclear, and thus require further investigation. In this study, our purpose was to investigate the role played by BolA-like protein (IbaG) in the pathogenicity of V. parahaemolyticus. We used homologous recombination to obtain the deletion strain ΔibaG and investigated the biological role of BolA family protein IbaG in V. parahaemolyticus. Our results showed that IbaG is a bacterial transcription factor that negatively modulates swimming capacity. Furthermore, overexpressing IbaG enhanced the capabilities of V. parahaemolyticus for swarming and biofilm formation. In addition, inactivation of ibaG in V. parahaemolyticus SH112 impaired its capacity for colonizing the heart, liver, spleen, and kidneys, and reduced visceral tissue damage, thereby leading to diminished virulence, compared with the wild-type strain. Finally, RNA-sequencing revealed 53 upregulated and 71 downregulated genes in the deletion strain ΔibaG. KEGG enrichment analysis showed that the two-component system, quorum sensing, bacterial secretion system, and numerous amino acid metabolism pathways had been altered due to the inactivation of ibaG. The results of this study indicated that IbaG exerts a considerable effect on gene regulation, motility, biofilm formation, and pathogenicity of V. parahaemolyticus. To the best of our knowledge, this is the first systematic study on the role played by IbaG in V. parahaemolyticus infections. Thus, our findings may lead to a better understanding of the metabolic processes involved in bacterial infections and provide a basis for the prevention and control of such infections

Porcine reproductive and respiratory syndrome virus inhibits MARC-145 proliferation via inducing apoptosis and G2/M arrest by activation of Chk/Cdc25C and p53/p21 pathway

Abstract Porcine reproductive and respiratory syndrome virus(PRRSV) is an important immunosuppressive virus which can suppresses infected cells proliferation. In this work, we examined PRRSV ability to manipulate cell cycle progression of MARC-145 cells and explored the potential molecular mechanisms. The results showed that PRRSV infection imposed a growth-inhibitory effect on MARC-145 cells by inducing cell cycle arrest at G2/M phase. This arrest was due to the significant decrease of Cdc2-cyclinB1 complex activity in PRRSV-infected cells and the activity reduction was a result of Cdc2 Tyr15 phosphorylation and the accumulation of Cdc2 and cyclinB1 in the nucleus. Not only elevated Wee1 and Myt1 expression and inactivated Cdc25C, but also increase of p21 and 14–3-3σ in a p53-dependent manner caused the inhibitory Tyr15 phosphorylation of Cdc2. PRRSV infection also activated Chk1. Our data suggest PRRSV infection induces G2/M arrest via various molecular regulatory mechanisms. These results provide a new insights for PRRSV pathogenesis