PD-1/PD-L1 costimulatory pathway-induced mouse islet transplantation immune tolerance

BACKGROUND

Programmed death-1/PD-1 ligand-1 (PD-1/PD-L1) costimulatory signals may play an important role in T-cell-induced immune response. The aim of this study is to investigate the role of the PD-1/PD-L1 costimulatory pathway on immunotolerance induction in mouse pancreatic islet transplantation.

METHODS

Full-length mouse PD-L1 cDNA was subcloned into pShuttle-GFP-CMV(-) shuttle plasmid. The product was cut by certain restriction endonuclease and ligated with pAdxsi vector. The adenovirus bone plasmid was transformed into DH5α-competent bacteria. After linearization, the recombined adenovirus DNA was transfected into 293 cells for package and amplification. Streptozotocin was injected intraperitoneally into C57BL/6 (H-2(b)) mouse to induce diabetic model recipient. Recipients were randomly divided into 3 groups. Group A was the control. Group B and group C were injected with Ad-EGFP and Ad-PD-L1 through the tail vein, respectively, 1 day before islet transplantation. The 300 to 400 islets of DBA/2 (H-2(d)) were transplanted into the renal subcapsular space of the diabetic model recipient. We monitored and analyzed the blood glucose levels and the survival time of grafts after transplantation.

RESULTS

Recombinant adenovirus Ad-PD-L1 had high efficiency expression of PD-L1 in recipient mouse. The blood glucose concentration of mice in the Ad-PD-L1 gene treatment group was obviously lower than that of the control and Ad-EGFP treatment groups and was stable and kept within the normal range at post-transplant 21 days. The survival time of grafts in the Ad-PD-L1 group (27.6 ± 3.5 days) was significantly longer than in the control (7.8 ± 0.33 days) and Ad-EGFP groups (7.6 ± 0.59 days), P < .01. Mixed lymphocyte response showed a specific decrease reaction of recipient lymphocyte vs donor lymphocyte. Flow cytometry detection showed that unsplit cells occupied 90% of recipient mouse lymphocytes, but unsplit cells among normal C57BL/6 mouse lymphocytes without Ad-PD-L1 gene treatment were 51 in the control group. The differences between them were significant (P < .01).

CONCLUSION

Recombinant adenovirus Ad-PD-L1 has been successfully constructed. In mouse pancreatic islet transplantation, it can suppress the activation of recipient T lymphocyte through the PD-1/PD-L1 costimulatory pathway, and significantly prolong the survival time of grafts.

Haemocyanin is essential for embryonic development and survival in the migratory locust

Haemocyanins are commonly known as copper-containing oxygen carriers within the haemolymph of arthropods, and have been found in many orders of insects. However, it remains unresolved why haemocyanins persist in insects that possess elaborate tracheal systems for oxygen diffusion to cells. Here we identified haemocyanins in the migratory locust Locusta migratoria that consists of two distinct subunits, Hc1 and Hc2. Genomic sequence analysis indicated that Hc1 and Hc2 have four and three gene copies, respectively, which may have evolved via gene duplication followed by divergent evolution of introns. The two subunits exhibit abundant and embryonic-specific expression at the mRNA and protein level; their expression peaks in the mid-term embryo and is not detectable in the late nymphal and adult stages. A larger proportion of the haemocyanins is present in the yolk compared with that in the embryo. Immunostaining shows that haemocyanins in the embryo are mainly expressed in the epidermis. Knockdown of Hc1 and Hc2 results in significant embryonic developmental delay and abnormality as well as reduced egg hatchability, ie the proportion of hatched eggs. These results reveal a previously unappreciated and fundamental role for haemocyanins in embryonic development and survival in insects, probably involving the exchange of molecules (eg O2 ) between the embryo and its environment.

INHIBITORY ACTION OF CoCl2-INDUCED MCF-7 CELL HYPOXIA MODEL OF BREAST CANCER AND ITS INFLUENCE ON VASCULAR ENDOTHELIAL GROWTH FACTOR

Breast cancer, a malignant tumor frequently occurring in females, is traditionally treated with excision. In the search for a new treatment, we analyzed the influence of CoCl2 on MCF-7 cell proliferation of breast cancer and tumor angiogenesis factor and discussed the results. Having applied CoCl2 as chemical hypoxia-induced agent, in-vitro MCF-7 cell hypoxia model of breast cancer was established, after which methyl thiazolyl tetrazolium (MTT) staining was performed in detecting inhibitory action of CoCl2 to proliferation of MCF-7 cells cultured in-vitro, and inverted phase contrast microscope was adopted to observe morphological changes of MCF-7 cell in hypoxia model. Furthermore, reverse transcription-polymerase chain reaction (RT-PCR) was made to determine how CoCl2 influences mRNA expression changes of hypoxia inducible factor-1α (HIF-1α), chemokine receptor-4 (CXCR4) and vascular endothelial growth factor (VEGF) in MCF-7 cells. Western blot was designed to study and record data on the influence of CoCl2 on protein expression changes of HIF-1α, CXCR4 and VEGF. As a result, CoCl2 was proved to control MCF-7 cell proliferation and increase expression of HIF-1α, CXCR4 and VEGF.

All optical mode controllable Er-doped random fiber laser with distributed Bragg gratings

An all-optical method to control the lasing modes of Er-doped random fiber lasers (RFLs) is proposed and demonstrated. In the RFL, an Er-doped fiber (EDF) recoded with randomly separated fiber Bragg gratings (FBG) is used as the gain medium and randomly distributed reflectors, as well as the controllable element. By combining random feedback of the FBG array and Fresnel feedback of a cleaved fiber end, multi-mode coherent random lasing is obtained with a threshold of 14 mW and power efficiency of 14.4%. Moreover, a laterally-injected control light is used to induce local gain perturbation, providing additional gain for certain random resonance modes. As a result, active mode selection of the RFL is realized by changing locations of the laser cavity that is exposed to the control light.

Stark effect induced microcavity polariton solitons

This paper proposes a way of generating polariton solitons (PSs) in a semiconductor microcavity using Stark effect as the trigger mechanism. A Stark pulse performing as the writing beam is used to excite non-resonant fluctuations of polariton, which finally evolves into bright PSs. It is found that a branch of PS solutions versus pump parameters could be found through optimizing parameters of the Stark pulse, and polarization of the generated PS is dependent on the writing beam.

Single nucleotide polymorphism analysis of the endopolygalacturonase gene in peach and its potential use in crossbreeding programs

Single nucleotide polymorphisms (SNPs) are the most abundant sequence variations found in plant genomes and are widely used as molecular genetic markers in genetic diversity studies and crossbreeding programs. In this study, we examined 113 DNA sequences of the endopolygalacturonase (endo-PG) gene from 67 peach accessions and found a total of 56 SNPs and 6 insertion/deletions (indels), with a frequency of 3, 1, and 3% for the transitions, transversions, and indels, respectively. Meanwhile, the majority of the observed SNPs were found in the intron regions, while only 2 variable sites and a single indel were detected in the exon regions. A dendrogram was obtained using neighbor-joining cluster analysis and divided into 2 main groups, providing evidence that most of the accessions of the clingstone nonmelting flesh phenotypes generally clustered together and were comparatively nonrelated to the "stony hard" peach cultivars, which were in a different branch altogether. Furthermore, 4 major haplotypes were formed and 3 cleaved amplified polymorphic sequence primer sets were mined according to fruit texture and stone adhesion, displaying their potential as candidate molecular markers for discriminating genotypes. This research will assist peach genetic enhancement by introducing a novel crossbreeding strategy.

Production of [Formula: see text] and [Formula: see text] in proton-proton collisions at [Formula: see text] 7 TeV

The production of the strange and double-strange baryon resonances ([Formula: see text], [Formula: see text]) has been measured at mid-rapidity ([Formula: see text][Formula: see text]) in proton-proton collisions at [Formula: see text] [Formula: see text] 7 TeV with the ALICE detector at the LHC. Transverse momentum spectra for inelastic collisions are compared to QCD-inspired models, which in general underpredict the data. A search for the [Formula: see text] pentaquark, decaying in the [Formula: see text] channel, has been carried out but no evidence is seen.

Exclusive J/ψ photoproduction off protons in ultraperipheral p-Pb collisions at √(s(NN))=5.02 TeV

We present the first measurement at the LHC of exclusive J/ψ photoproduction off protons, in ultraperipheral proton-lead collisions at sqrt[s_{NN}]=5.02  TeV. Events are selected with a dimuon pair produced either in the rapidity interval, in the laboratory frame, 2.5<y<4 (p-Pb) or -3.6<y<-2.6 (Pb-p), and no other particles observed in the ALICE acceptance. The measured cross sections σ(γ+p→J/ψ+p) are 33.2±2.2(stat)±3.2(syst)±0.7(theor)  nb in p-Pb and 284±36(stat)_{-32}^{+27}(syst)±26(theor)  nb in Pb-p collisions. We measure this process up to about 700 GeV in the γp center of mass, which is a factor of two larger than the highest energy studied at HERA. The data are consistent with a power law dependence of the J/ψ photoproduction cross section in γp energies from about 20 to 700 GeV, or equivalently, from Bjorken x scaling variable between ∼2×10^{-2} and ∼2×10^{-5}, thus indicating no significant change in the gluon density behavior of the proton between HERA and LHC energies.

Measurement of prompt D-meson production in p-Pb collisions at √(s(NN))=5.02 TeV

The p_{T}-differential production cross sections of the prompt charmed mesons D^{0}, D^{+}, D^{*+}, and D_{s}^{+} and their charge conjugate in the rapidity interval -0.96<y_{cms}<0.04 were measured in p-Pb collisions at a center-of-mass energy sqrt[s_{NN}]=5.02  TeV with the ALICE detector at the LHC. The nuclear modification factor R_{pPb}, quantifying the D-meson yield in p-Pb collisions relative to the yield in pp collisions scaled by the number of binary nucleon-nucleon collisions, is compatible within the 15%-20% uncertainties with unity in the transverse momentum interval 1<p_{T}<24  GeV/c. No significant difference among the R_{pPb} of the four D-meson species is observed. The results are described within uncertainties by theoretical calculations that include initial-state effects. The measurement adds experimental evidence that the modification of the momentum spectrum of D mesons observed in Pb-Pb collisions with respect to pp collisions is due to strong final-state effects induced by hot partonic matter.

Measurement of quarkonium production at forward rapidity in [Formula: see text] collisions at [Formula: see text]TeV

The inclusive production cross sections at forward rapidity of [Formula: see text], [Formula: see text], [Formula: see text](1S) and [Formula: see text](2S) are measured in [Formula: see text] collisions at [Formula: see text] with the ALICE detector at the LHC. The analysis is based on a data sample corresponding to an integrated luminosity of 1.35 pb[Formula: see text]. Quarkonia are reconstructed in the dimuon-decay channel and the signal yields are evaluated by fitting the [Formula: see text] invariant mass distributions. The differential production cross sections are measured as a function of the transverse momentum [Formula: see text] and rapidity [Formula: see text], over the ranges [Formula: see text] GeV/c for [Formula: see text], [Formula: see text] GeV/c for all other resonances and for [Formula: see text]. The measured cross sections integrated over [Formula: see text] and [Formula: see text], and assuming unpolarized quarkonia, are: [Formula: see text] [Formula: see text]b, [Formula: see text] [Formula: see text]b, [Formula: see text] nb and [Formula: see text] nb, where the first uncertainty is statistical and the second one is systematic. The results are compared to measurements performed by other LHC experiments and to theoretical models.

Effect of high-fructose corn syrup on the acidogenicity, adherence and biofilm formation of Streptococcus mutans

BACKGROUND

Although high-fructose corn syrup (HFCS) as a kind of sugar has been widely used in manufactured foods recently, there is little information available regarding its cariogenicity. The aim of this study was to evaluate the cariogenic potential of HFCS.

METHODS

Streptococcus mutans UA159 was inoculated into HFCS media and cultivated. The pH of each culture was measured to assess acidogenicity. Spectrophotometric turbidity was measured to determine the percentage of adherence. Confocal laser scanning microscopy and SYTO-9 staining were employed to observe biofilm formation. Sucrose media was used as a positive control.

RESULTS

The ΔpH in HFCS media was significantly larger than that in sucrose media and the pH in HFCS media decreased faster (p < 0.05). The percentage of adherence of S. mutans in HFCS media was significantly lower than that in sucrose media (p < 0.05). The biofilm formed in sucrose media was significantly thicker than that in HFCS media (p < 0.05).

CONCLUSIONS

The results of this study suggest that the cariogenicity of S. mutans in the presence of HFCS may differ compared to its cariogenicity in the presence of sucrose. Further in vivo studies need to be undertaken to resolve this uncertainty.

The beam diagnostic instruments in Beijing radioactive ion-beam facilities isotope separator on-line

The beam diagnostic instruments for Beijing Radioactive Ion-beam Facilities Isotope Separator On-Line are introduced [B. Q. Cui, Z. H. Peng, Y. J. Ma, R. G. Ma, B. Tang, T. Zhang, and W. S. Jiang, Nucl. Instrum. Methods 266, 4113 (2008); T. J. Zhang, X. L. Guan, and B. Q. Cui, in Proceedings of APAC 2004, Gyeongju, Korea, 2004, http://www.jacow.org, p. 267]. For low intensity ion beam [30-300 keV/1 pA-10 μA], the beam profile monitor, the emittance measurement unit, and the analyzing slit will be installed. For the primary proton beam [100 MeV/200 μA], the beam profile scanner will be installed. For identification of the nuclide, a beam identification unit will be installed. The details of prototype of the beam diagnostic units and some experiment results will be described in this article.

An ion source module for the Beijing Radioactive Ion-beam Facility

An ion source module is developed for Beijing Radioactive Ion-beam Facility. The ion source module is designed to meet the requirements of remote handling. The connection and disconnection of the electricity, cooling and vacuum between the module and peripheral units can be executed without on-site manual work. The primary test of the target ion source has been carried out and a Li(+) beam has been extracted. Details of the ion source module and its primary test results are described.

The development of the high intensity electron cyclotron resonance ion source at China Institute of Atomic Energy

High-current microwave ion source has been under development over 15 years for accelerator driven sub-critical system research at China Institute of Atomic Energy, and the beam intensity higher than 140 mA proton beam is produced by this ion source with long lifetime and high reliability. The emittance of high intensity continue-wave and pulse beam is measured on a test-bench in the laboratory. Based on the good performance of this proton ion source, a new 120 mA deuterium ion source is proposed for a high intensity neutron generator. The ion source details and status will be presented.

Disorder effect on the integer quantum Hall effect in trilayer graphene

We numerically investigate the disorder effect on the integer quantum Hall effect in a trilayer graphene (TLG) system by use of the Kubo formula. For a clean sample, both Bernal (ABA) and rhombohedral (ABC) stacked TLGs display the same quantum rule with abnormal quantized Hall plateaus σxy = νe(2)/h (ν =± 6, ± 10, ± 14,…) in the band center and normal quantized Hall plateaus at the band edges. In the presence of disorder, the Hall plateaus become obscure and the higher plateaus disappear first with the increase of the disorder; however, the Hall plateaus of the ABA-stacked TLG are destroyed more readily in comparison with the ABC-stacked one. The longitudinal conductance minimums of the system corresponding to the Hall plateaus become narrower and thinner with disorder, and those of the ABC-stacked TLG are comparatively more stable than those of the ABA structure. The findings indicate that the l = 3 chiral quasiparticles with cubic energy dispersion in ABC-stacked TLG have comparatively stronger immunity to the disorder than the l = 1 and 2 chiral quasiparticles in the ABA counterpart.

Energy dependence of the transverse momentum distributions of charged particles in pp collisions measured by ALICE

Differential cross sections of charged particles in inelastic pp collisions as a function of p_T have been measured at [Formula: see text] at the LHC. The p_T spectra are compared to NLO-pQCD calculations. Though the differential cross section for an individual [Formula: see text] cannot be described by NLO-pQCD, the relative increase of cross section with [Formula: see text] is in agreement with NLO-pQCD. Based on these measurements and observations, procedures are discussed to construct pp reference spectra at [Formula: see text] up to p_T=50 GeV/c as required for the calculation of the nuclear modification factor in nucleus-nucleus and proton-nucleus collisions.