Stable Agrobacterium-mediated transformation of the halophytic Leymus chinensis (Trin.)

In this study, an efficient procedure for stable Agrobacterium-mediated transformation of Leymus chinensis (Trin.) was established. Agrobacterium tumefaciens strain EHA105, harboring a binary vector pCAMBIA2300, was used for transformation, along with a sweet potato 2-cysteine peroxiredoxin (2-Cys Prx) gene under the control of the stress-inducible sweet potato anionic peroxidase 2 (SWPA2) promoter and the neomycin phosphotransferase (nptII) gene under the control of the cauliflower mosaic virus (CaMV) 35 S promoter. We found that a one-month-old callus derived from mature seeds could be efficiently transformed. Seven-day preculture followed by inoculation with the addition of 100 μmolL-1 acetosyringone (AS) and then a 3 day co-cultivation were performed before selection. Selection of transgenic shoots was done in the presence of 150 mgL-1 kanamycin (KM). An optical density at a wavelength of 600 nm (OD600) of approximately 0.4 for A. tumefaciens infection solution and 20 min of infection time gave the highest transformation efficiency. Polymerase chain reaction (PCR) analysis of KM-resistant plants and newly regenerated rhizomes revealed stable transformation of the 2-Cys Prx gene and the nptII gene, with the highest transformation frequency of 4.93%. RT-RCR analysis was conducted using salt stressed transgenic plants, and the results suggested that 2-Cys Prx had low transcription levels under non-stressed conditions, and increased transcription after 6 h of 200 mM NaCl stress. This gene continued to demonstrate high levels of transcription until 6 h after withdrawal of stress, with a slow recovery. The method reported herein provides a direct opportunity for improvement of the quality traits of L. chinensis via genetic transformation.Keywords: Leymus chinensis, Agrobacterium-mediated transformation, 2-Cys peroxiredoxin, gene transformatio

Porous silicon nanoparticles for cancer photothermotherapy

The in vitro cell tests and in vivo animal tests were performed to investigate the feasibility of the photothermal therapy based on porous silicon (PSi) in combination with near-infrared (NIR) laser. According to the Annexin V- fluorescein isothiocyanate Apoptosis assay test results, the untreated cells and the cells exposed to NIR laser without PSi treatment had a cell viability of 95.6 and 91.3%, respectively. Likewise, the cells treated with PSi but not with NIR irradiation also had a cell viability of 74.4%. Combination of these two techniques, however, showed a cell viability of 6.7%. Also, the cell deaths were mostly due to necrosis but partly due to late apoptosis. The in vivo animal test results showed that the Murine colon carcinoma (CT-26) tumors were completely resorbed without nearly giving damage to surrounding healthy tissue within 5 days of PSi and NIR laser treatment. Tumors have not recurred at all in the PSi/NIR treatment groups thereafter. Both the in vitro cell test and in vivo animal test results suggest that thermotherapy based on PSi in combination with NIR laser irradiation is an efficient technique to selectively destroy cancer cells without damaging the surrounding healthy cells

Two-dimensional heterogeneous photonic bandedge laser

We proposed and realized a two-dimensional (2D) photonic bandedge laser surrounded by the photonic bandgap. The heterogeneous photonic crystal structure consists of two triangular lattices of the same lattice constant with different air hole radii. The photonic crystal laser was realized by room-temperature optical pumping of air-bridge slabs of InGaAsP quantum wells emitting at 1.55 micrometer. The lasing mode was identified from its spectral positions and polarization directions. A low threshold incident pump power of 0.24mW was achieved. The measured characteristics of the photonic crystal lasers closely agree with the results of real space and Fourier space calculations based on the finite-difference time-domain method.Comment: 14 pages, 4 figure

A Review on 3D Printing for Customized Food Fabrication

AbstractThis study introduces the first generation food printer concept designs and workable prototypes that target to revolutionize customized food fabrication by 3D printing (3DP). Different from robotics-based food manufacturing technologies designed to automate manual processes for mass production, 3D food printing integrates 3DP and digital gastronomy technique to manufacture food products with customization in shape, colour, flavor, texture and even nutrition. This introduces artistic capabilities to fine dining, and extend customization capabilities to industrial culinary sector.The selected prototypes are reviewed based on fabrication platforms and printing materials. A detailed discussion on specific 3DP technologies and their associate dispensing/printing process for 3D customized food fabrication are reported for single and multi-material applications. Eventually, impacts of food printing on personalized nutrition, on-demand food fabrication, food processing technologies and process design are reported. Their applications in domestic cooking or catering services can not only provide an engineering solution for customized food design and personalized nutrition control, but also a potential machine to reconfigure a customized food supply chain

Over-expression of the CHS gene enhances resistance of Arabidopsis leaves to high light

Previous studies have suggested that high light (HL) stress causes photoinhibition in plants, while anthocyanins could protect the photosynthetic apparatus against photoinhibition. However, the photoprotection mechanism of anthocyanins is still ambiguous. We studied physiological responses and molecular changes for CHS-overexpression lines (CHS1, CHS2, CHS3), Arabidopsis thaliana ecotype Columbia (Col), and T-DNA insertion lines of CHS (tt4) under HL (200 μmol m−2 s−1) to explore the photoprotection mechanism of anthocyanins. The results showed that HL induced anthocyanin synthesis and accumulation. The leaves of CHS-overexpression lines turned reddest and the genes, including CHS, DFR, ANS, were expressed at highest levels. Thus, the CHS-overexpression lines maintained the highest photosynthetic capacity and suffered the least damage from HL of the three phenotypes. However, the CHS enzyme and anthocyanins were undetectable in tt4 during the experiment. Correspondingly, chlorophyll fluorescence parameters of tt4 declined greatly. The photosynthetic apparatus and cell membranes were also impaired dramatically. The physiological characteristics of Col were compared between CHS-overexpression lines and tt4. Together, the results suggest that over-expression of CHS gene enhances HL resistance by synthesizing more anthocyanins, that anthocyanins enhance the adaptability of plants to HL and that they maintain photosynthetic capacity via both antioxidation and attenuation of light.This work was funded by the National Key R&D Program of China (2017YFC1200105) and Guangdong Province Natural Science Foundation (2017A030313167, 2015A030311023). The study was also supported by the National Natural Science Foundation of China (31570398), Science and Technology Program of Guangzhou (20170701257) and Yang Cheng Scholar Program (10A040G)

Prognostic Value of Metastatic Tumoral Caveolin-1 Expression in Patients with Resected Gastric Cancer

Objective. Caveolin-1 (Cav-1), as the main component of caveolae, has complex roles in tumourigenesis in human malignancies. We investigated Cav-1 in primary and metastatic tumor cells of gastric cancer (GC) and its association with clinical outcomes. Methods. We retrieved 145 cases of GC who had undergone curative gastrectomy. The expression levels of Cav-1 was evaluated by immunohistochemistry, and its association with clinicopathological parameters and patient survival was analyzed. Results. High expression of Cav-1 protein of the GC in the stomach and metastatic lymph node was 12.4% (18/145) and 16.5% (15/91). In the multivariate analysis, tumoral Cav-1 protein in metastatic lymph node showed prognostic significance for relapse-free survival (RFS, HR, 3.934; 95% CI, 1.882–8.224; P=0.001) and cancer-specific survival outcome (CSS, HR, 2.681; 95% CI, 1.613–8.623; P=0.002). Among the GCs with metastatic lymph node, it remained as a strong indicator of poor prognosis for RFS (HR, 3.136; 95% CI, 1.444–6.810; P=0.004) and CSS (HR, 2.509; 95% CI, 1.078–5.837; P=0.032). Conclusion. High expression of tumoral Cav-1 protein in metastatic lymph node is associated with unfavorable prognosis of curative resected GC, indicating the potential of novel prognostic markers

Increasing late diagnosis in HIV infection in South Korea: 2000-2007

<p>Abstract</p> <p>Background</p> <p>The number of Koreans diagnosed with human immunodeficiency virus (HIV) infections is increasing annually; however, CD4+ T-cell counts at diagnosis have decreased. The purpose of the present study was to identify clinical and epidemiologic associations with low CD4+ T-cell counts at the time of HIV diagnosis in a Korean population.</p> <p>Methods</p> <p>Data from 2,299 HIV-infected individuals with initial CD4+ T-cell counts measured within 6 months of HIV diagnosis and reason for HIV testing were recorded and measured from 2000 to 2007. Data were selected from the database of the Korea Centers for Disease Control and Prevention. Late diagnosis was defined by CD4+ T-cell counts <200 cells/mm³. Reasons for HIV testing were analyzed using logistic regression including epidemiologic variables.</p> <p>Results</p> <p>A total of 858 individuals (37.3%) were included in the late diagnosis group. Individuals with a late diagnosis were older, exposed through heterosexual contact, and demonstrated clinical manifestations of acquired immunodeficiency syndrome (AIDS). The primary reason for HIV testing was a routine health check-up (41%) followed by clinical manifestations (31%) of AIDS. The proportion of individuals with a late diagnosis was higher in individuals tested due to clinical symptoms in public health centers (adjusted odds ratio [AOR], 17.3; 95% CI, 1.7-175) and hospitals (AOR, 4.9; 95% CI, 3.4-7.2) compared to general health check-up. Late diagnosis annually increased in individuals diagnosed by voluntary testing both in public health centers (PHCs, P = 0.017) and in hospitals (P = 0.063). Routine testing due to risky behaviors resulted in earlier detection than testing secondary to health check-ups, although this difference was not statistically significant (AOR, 0.7; P = 0.187). Individuals identified as part of hospital health check-ups more frequently had a late diagnosis (P = 0.001)</p> <p>Conclusions</p> <p>HIV infection was primarily detected by voluntary testing with identification in PHCs and by testing due to clinical symptoms in hospitals. However, early detection was not influenced by either voluntary testing or general health check-up. It is important to encourage voluntary testing for early detection to decrease the prevalence of HIV infection and AIDS progression.</p

MDR-1 gene expression is a minor factor in determining the multidrug resistance phenotype of MCF7/ADR and KB-V1 cells

AbstractThe relevance of MDR-1 gene expression to the multidrug resistance phenotype was investigated. Drug-resistant cells, KB-V1 and MCF7/ADR, constantly expressed mRNA of the MDR-1 gene and were more resistant to vinblastine and adriamycin than drug-sensitive cells, KB-3–1 and MCF7. The drug efflux rate of KB-V1 was the same as KB-3–1 although the MDR-1 gene was expressed in only the resistant cell. The higher intracellular drug concentration of KB-3–1 than KB-V1 was due to the large drug influx. In the case of MCF7 and MCF7/ADR, the influx and efflux of the drug had nearly the same pattern and drug efflux was not affected by verapamil. The amount of ATP, cofactor of drug pumping activity of P-glycoprotein, was not changed by the resistance. These observations suggested that drug efflux mediated by MDR-1 gene expression was not a major determining factor of drug resistance in the present cell systems, and that the drug resistance could be derived from the change in drug uptake and other mechanisms