Superoxide generated during the early imbibition is an excellent marker for evaluating seed vigor. In this paper, a new principle biosensor for non-invasive detection of seed vigor based on quantitative mea-surement of superoxide via selective probe 2-rnethyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo [1,2a] pyrazin-3-one (MCLA)-mediated chemiluminescence (CL) was developed. The biosensor, which used a compact single-photon counting module (SPCM) to collect the CL signal, could evaluate seed vigor in vivo. Benefiting from the high CL efficiency of MCLA reacting with superoxide and high sensitivity of the SPCM technique, the trace superoxide generated by dry seeds under storage state can be detected to achieve rapid and non-invasive determination of the seed vigor. In comparison with the traditional methods for fast measuring seed vigor based on measurement of physiological and biochemical properties. our pro-posed technique has significant advantages such as low cost, simplicity, convenient operation and short time consuming. To demonstrate the utility of the SyStem, it was applied to evaluate MCLA-mediated CL of three different plant species wheat (Ze Yu No.2), maize (Tai Cu No.1 and 2) and rice (Jing Dao No.21) seeds with different degrees of aging. The experimental results suggested that there was an excellent pos-itive correlation between the seed vigor assessment from quantitative TTC-test and the detection based on MCLA-mediated CL of superoxide measurement. The new principle of seed vigor measurement is a challenge and breakthrough to conventional method of seed vigor determination and may be a potential technique of the next generation seed vigor detection.

Single-walled carbon nanotubesSWNTs have a high op-tical absorbance in the near-infraredNIR region. In this special op-tical window, biological systems are known to be highly transparent. The optical properties of SWNTs provide an opportunity for selective photothermal therapy for cancer treatment. Specifically, CoMoCAT

The application of single-walled carbon nanotubes (SWNTs) in the field of biomedicine is becoming an entirely new and exciting topic. In this study, a novel functional SWNT based on an integrin αvβ3 monoclonal antibody was developed and was used for cancer cell targeting in vitro. SWNTs were first modified by phospholipid-bearing polyethylene glycol (PL-PEG). The PL-PEG functionalized SWNTs were then conjugated with protein A. A SWNT-integrin αvβ3 monoclonal antibody system (SWNT-PEG-mAb) was thus constructed by conjugating protein A with the fluorescein labeled integrin αvβ3 monoclonal antibody. In vitro study revealed that SWNT-PEG-mAb presented a high targeting effiency on integrin αvβ3-positive U87MG cells with low cellular toxicity, while for integrin αvβ3-negative MCF-7 cells. the system had a low targeting efficiency, indicating that the high targeting to U87MG cells was due to the specific integrin targeting of the monoclonal antibody. In conclusion. SWNT-PEG-mAb developed in this research is a potential candidate for cancer imaging and drug delivery in cancer targeting therapy.

The formation of circular dorsal ruffles upon growth factor stimulation facilitates the static cells fo r subsequent motility. Low-power laser irradiation (LPLI) has been shown to exert some promotive effects on migration and proliferation in various cell types. It is unclear whether LPLI could induce the formation of circular ruffles. In this study, using confocal fluorescence microscope, we for the first time demonstrated that LPLI could induce the production of circular ruffle stru ctu res in COS-7 cells. These structu res were proved to be actin-ased and originated from membrane microdomains enriched in cholesterol. Ras was shown to be activated by LPLI and expression of YFP-H-Ras (N 17), a dominant negative H-Ras, blocked the generation of circular ruffles induced by LPLI. Wortmannin, P13K inhibitor, potently suppressed the fo rmation of LPLI-induced circular ruffles in a dose-dependent manner. However, blocking the activation of PKC, which was activated during LPLI-induced cell proliferation in our previous study, had no effect on the formation of circular ruffles. Thus, both H - Ras and P13K were required fo r the fo rmation of circular ruffles induced by LPLI and the generation of circular ruffles provides new information for the mechanisms of biological effects of LPLI.

Low-power laser irradiation (LPLI) can stimulate cell proliferation th rough a wide network of signals. Akt is an important protein kinase in modulating cell proliferation. In this study, using real-time single-cell analysis, we investigated the activity of Akt and its effects on cell proliferation induced by LPLI in African green monkey SV40-transformed kidney fibroblast cells (COS-7). We utilized a recombinant fluorescence resonance energy transfer (FRET) Akt probe (BKAR) to dynamically detect the activation ofAkt after LPLI treatment. Our results show that LPLI induced a gradual and continuous activation ofAkt. Moreover, the activation of Akt can be completely abolished by wortmannin, a speciflc inhibitor of P13K, suggesting that the activation of Akt caused by LPLI is a P13K-dependent event. Src family is involved in Akt activation as demonstrated by the part: inhibition of Akt activity in samples treated with PPI (an inhibitor of Src family). In contrast, loading Go 6983, a PKC inhibitor, did not affect this response. Further experiments performed using GFP-Akt fluorescence imaging and Western blot analysis demonstrate that, the activation of Akt is a multi-step process in response to LPLI, involving membrane recruitment, phosphorylation, and membrane detachment. LPLI promotes cell proliferation through P13 K/Akt activation since the cell viability was significantly inhibited by P13 K inhibito r. All these studies create a concernful conclusion that P13 K/Akt signaling pathway is well involved in LPLI triggered cell proliferation that acts as a time- and dose-dependent manner.

The broad-spectrum expression of telomerase in most malignancies makes it a promising target for a cancer diagnostic and prognostic tool. Conventional polymerase chain reaction (PCR)-based telomerase activity assay is highly sensitive but susceptible to amplification-related errors. Here, we present a novel approach to telomerase activity detection. The detection of telomerase activity is accomplished by the hybridization of electrochemilumi-nescence (ECL) nanoprobes to telomerase reaction prod-ucts, subsequent capture by magnetic beads, and in situ measurement of the light signal from ECL nanoprobes. The ECL intensity directly reflects the quantity of telom-erasereactionproducts, thustelomeraseactivity. Thehigh sensitivity afforded by the current magnetic bead and nanoparticle based ECL detection platform allows mea-suring of telomerase activity from as little as 500 cultured cancer cells in crude cell extracts without the PCR amplification of telomerase reaction products. In addition, a comparative study of the ECL nanoprobe and linear telomere antisense ECL probe was executed. By the employment of the ECL nanoprobe, a gain of about 100-fold elevation of sensitivity was determined. The method described here is ideal for telomer aseactivity analysis due to its reliability and high sensitivity.

Noninvasive and reliable quantification of rheological char-acteristics in the nucleus is extremely useful for fundamental research and practical applications in medicine and biology. This study exam-ines the use of fluorescence correlation spectroscopy (FCS) to nonin-vasively determine nucleoplasmic viscosity(ηnu), an important pa-rameter of nucleoplasmic rheology. Our FCS analyses show thatnu of lung adenocarcinomaASTC-a-1 and HeLa cells are 1.77±0.42 cP and 1.40±0.27 cP, respectively, about three to four times larger than the water viscosity at 37℃.ηnu was reduced by 31 to 36% upon hypotonic exposure and increased by 28 to 52% from 37 to 24℃. In addition, we found that ηnu of HeLa cells reached the lowest value in the S phase and that there was no significant differ-ence of ηnu between in the G1 and G2 phases. Last, nucleoplasmic viscosity was found to be larger than cytoplasmic viscosity in both HeLa and ASTC-a-1 cells. These results indicate that FCS can be used as a noninvasive tool to investigate the microenvironment of living cells. This is the first report on the measurement of ηnu in living cells synchronized in the G1, S, and G2 phases.

In this paper we study the transmission prop-erties of light through generalized Thue-Morse (GTM (m, n))aperiodic superlattices and obtain the formulae of the transmission coefficients (TCs) analytically at the central wavelength, which are confirmed by numerical simula-tions. It is found that: (1) all of the lst generation systems are transparent to the substrates medium B; (2) GTM(m, 2j) systems are transparent to the substrates medium B; (3) GTM (2i, 2j+1) systems are translucent to the sub-strates medium B except the lst generation; and (4) when i≠j, transmission through GTM (2i+1, 2j+l) systems attenuates rapidly with the increase of generation number I and sequence parameters m, n. On the other hand, the po-sitional correlations between the constituents of GTM (m, n) aperiodic superlattices responsible for the resonant states are also discussed. Based on the conclusions we study the properties of the amplitude of the electric field vector and find that they are different from those of periodic lattices and chaotic systems.

We present a thermal gradient convective polymerase chain reaction (PCR) for parallel DNA amplification with different annealing temperatures. The thermal gradient for microfluidic gradient PCR is produced by an innovative fin design whose formation principle is given. Without the need for a pump, the buoyancy forces continuously circulate reagents in a closed loop through different thermal zones, which brings self-actuated convective-flow PCR. In our prototype, we measured a temperature difference of about 45℃ along the gradient direction on the copper flake (45×40×4mm). When the temperature of the hot zone is 90-97℃ and the temperature of the cold zone is 60-70℃, the convection triggered two-temperature amplification of 112-bp fragment of Escherichia coli DNA. The time for amplification is less than 45 min. Interestingly, parallel DNA amplification with different annealing temperatures ranging from 60 t0 70℃ was performed by this method. The PCR thermocycler demonstrated herein can be further scaled down and the loop Iength can be further reduced, and therefore the PCR times can be further reduced. These devices are suited as a platform for a new generation of low-power, portable DNA analysis systems.

Single-walled carbon nanotubes(SWNT) in a polyethyl-eneghycol solution are a biocompatible transporters with strong op-tical absorption in the near-infrared region, in which the biological tissue is almost transparent with very low absorbance. Here, antibody-functionalized SWNTs for tumor early detection with photoacoustic molecular imaging in vivo are reported. To lay the groundwork for this goal and insure system stability, images were collected in tissue simu-lating phantoms to determine appropriate detectable concentrations of SWNTs. Preliminary in vitro and in vivo results showed that a high contrast and a high efficient targeting of integrin αvβ3 positive U87 human glioblastoma tumours in mice could be achieved. The nontox- icity of functionalized SWNTs has also been demonstrated in our ex-periment; this feature ensures that SWNTs can be used for clinical applications. This study suggests that photoacoustic molecular imag-ing with antibody-functionalized SWNTs has the potential to be an effective early tumor diagnosis method.