Ultrafast attosecond-magnetic-field generation of the charge migration process based on HeH2+ and H2 + electronically excited by circularly polarized laser pulses.

The ultrafast process by the electron in molecular ions from one site or region to another that has come to be known as charge migration (CM), which is of fundamental importance to photon induced chemical or physical reactions. In this work, we study the electron current and ultrafast magnetic-field generation based on CM process of oriented asymmetric (HeH2+) and symmetric (H2 +) molecular ions. Calculated results show that they are ascribed to quantum interference of electronic states for these molecular ions under intense circularly polarized (CP) laser pulses. The two scenarios of (i) resonance excitation and (ii) direct ionization are considered through appropriately utilizing designed laser pulses. By comparison, the magnetic field induced by the scenario (i) is stronger than that of scenario (ii) for molecular ions. However, the scheme (ii) is very sensitive to the helicity of CP field, which is opposite to the scenario (i). Moreover, the magnetic field generated by H2 + is stronger than that by HeH2+ through scenario (i). Our findings provide a guiding principle for producing ultrafast magnetic fields in molecular systems for future research in ultrafast magneto-optics.

Shell-Isolated Nanoparticle-Enhanced Luminescence of Metallic Nanoclusters.

Metallic nanoclusters (NCs) have molecular-like structures and unique physical and chemical properties, making them an interesting new class of luminescent nanomaterials with various applications in chemical sensing, bioimaging, optoelectronics, light-emitting diodes (LEDs), etc. However, weak photoluminescence (PL) limits the practical applications of NCs. Herein, an effective and facile strategy of enhancing the PL of NCs was developed using Ag shell-isolated nanoparticle (Ag SHIN)-enhanced luminescence platforms with tuned SHINs shell thicknesses. 3D-FDTD theoretical calculations along with femtosecond transient absorption and fluorescence decay measurements were performed to elucidate the enhancement mechanisms. Maximum enhancements of up to 231-fold for the [Au7Ag8(C≡CtBu)12]+ cluster and 126-fold for DNA-templated Ag NCs (DNA-Ag NCs) were achieved. We evidenced a novel and versatile method of achieving large PL enhancements with NCs with potential for practical biosensing applications for identifying target DNA in ultrasensitive surface analysis.

Neuropilin1 silencing impairs the proliferation and migration of cells in pancreatic cancer.

BACKGROUND: Neuropilin1 (NRP1) participates in cancer cell proliferation, migration, and metastasis as a multifunctional co-receptor by interacting with multiple signal pathways, but few studies have addressed the precise function of NRP1 in pancreatic cancer (PACA) cells. We aimed to study whether NRP1 gene silencing involved in the proliferation and migration of PACA cells in vitro. METHODS: A lentiviral vector expressing NRP1 shRNA was constructed and transfected into human PACA cells (CFPAC-1 and PANC-1). The expression of NRP1 protein and mRNA was detected by Western blot and quantitative real-time polymerase chain reaction (qRT-PCR) assay, respectively. CCK-8 assay, wound healing assay, and transwell assay were conducted to examine the effect of NRP1 silencing on cells proliferation and migration capability. RESULTS: Results of qRT-PCR and Western blot showed successfully established, stably transfected shRNA-NRP1 cells in PACA cells. The proliferation capacity of PACA cells in NRP1 shRNA group was lower significantly than that in the negative control (NC) group (P < .05). The invasion and migration capability of PACA cells in NRP1 shRNA group was lower significantly than that in the NC group (P < .01). CONCLUSIONS: NRP1-shRNA lentiviral interference vectors can effectively decrease NRP1 gene expression in PACA cells, thereby inhibiting cells proliferation and migration, which provides a basis for finding a valuable therapeutic target for PACA therapy.

The protective effects of a novel polysaccharide from Lentinus edodes mycelia on islet ß (INS-1) cells damaged by glucose and its transportation mechanism with human serum albumin.

High glucose can lead to toxicity on islet ß cells. The protective effects of a novel Lentinus edodes mycelia polysaccharide (LMP) on INS-1 cells damaged by glucose were investigated. Cell viability, lactate dehydrogenase (LDH) release, cell apoptosis, intracellular reactive oxygen species (ROS), superoxide dismutase (SOD) activity, and malondialdehyde (MDA) content were detected. P38 MAPK, JNKand NF-κB pathways were analyzed to reveal the inhibitory mechanism of LMP on glucose-induced INS-1 cells toxicity. The results showed that LMP could decrease cellular oxidative stress, reduce intracellular ROS levels, decrease MDA content and increase SOD activity. Furthermore, the glucose-induced cell apoptosis in cells were inhibited by regulating the expression of Bax, Bcl-2, cleaved caspase­3 and cleaved caspase­1. Cell signaling pathway analysis revealed that LMP could inhibit the activation of p38 MAPK, JNK, NF-κB pathways and activate Nrf2 pathway. To further explore the possible transportation mechanism of LMP with human serum albumin (HSA), ultraviolet-visible absorption spectroscopy and fluorescence spectroscopy were used to evaluate the interaction between LMP and HSA. The results showed that LMP-HSA complex was formed, which would be helpful for explaining the transportation mechanism in vivo. These results suggested that LMP might be a new therapeutic candidate to alleviate the high glucose toxicity.

Isocitrate lyase from Mycobacterium tuberculosis promotes survival of Mycobacterium smegmatis within macrophage by suppressing cell apoptosis.

BACKGROUND: Isocitrate lyase (ICL) was previously demonstrated to play a pivotal role in the intracellular metabolism of Mycobacterium tuberculosis (MTB). Presently several lines of evidence suggest that ICL from MTB (MTB-ICL) may play some roles in the interaction between MTB and host macrophage. However, there has been no research on the interaction between MTB-ICL and host macrophage. METHODS: MTB-icl and M. smegmatis (MS)-icl genes were amplified by polymerase chain reaction (PCR) and cloned into the E. coli-mycobacterium shuttle plasmid pUV15 to obtain recombinant shuttle plasmids pMTB-icl and pMS-icl. Following transformation into MS by electroporation, the expression of pMTB-icl and pMS-icl was verified by reverse transcriptase (RT)-PCR. The expression of recombinant plasmids derived from pUV15 when rMS was phagocytized by macrophage was also verified via fluorescence microscope. Ms 1 - 2c, rMS-pUV15, rMS-pMS-icl and rMS-pMTB-icl were used to infect RAW264.7 cells and the survival of intracellular MS was monitored by bacterial culture at 0, 24 and 48 hours after infection. The culture supernatants from macrophage infected by Ms 1 - 2c, rMS-pUV15, rMS-pMS-icl and rMS-pMTB-icl were collected and the interferon (IFN)-gamma and nitric oxide (NO) concentrations were measured by ELISA or by Griess assay, respectively. The apoptosis of macrophage was assayed by the in situ TUNEL technique. RESULTS: RT-PCR showed that both pMTB-icl and pMS-icl could be expressed in MS. Fluorescence microscopic observation showed that recombinant plasmids derived from pUV15 (pUV15-IG) could also be expressed in MS when MS were phagocytized by macrophage. Bacterial culture data demonstrated that rMS-pMTB-icl exhibited significantly increased intracellular survival in the murine macrophage cell line RAW264.7 compared with Ms 1 - 2c, rMS-pUV15 and rMS-pMS-icl. This increased intracellular survival was not accompanied by the upregulation of IFN-gamma and NO in host macrophage. But a lower apoptosis rate of macrophages infected with rMS-pMTB-icl was observed when compared with macrophages infected with other strains of MS. CONCLUSIONS: MTB-ICL could promote the intracellular survival of MS. Suppressing the apoptosis of host macrophage may be one of the important mechanisms involved in this increased intracellular survival.

[Effects of isocitrate lyase from Mycobacterium tuberculosis on the survival of Mycobacterium smegmatis in macrophage and mechanism thereof].

OBJECTIVE: To investigate the effects of isocitrate lyase (ICL) from Mycobacterium tuberculosis (MTB-icl) on the survival of Mycobacterium smegmatis (MS) in macrophage and illuminate the possible mechanisms. METHODS: MTB-icl gene was amplified by PCR and cloned into Ecoli-Mycobacterium shuttle plasmid pUV15 to obtain recombinant shuttle plasmid pUV15-icl expressing ICL-GFP. The recombinant shuttle plasmid pUV15-icl and blank plasmid pUV15 were induced into MS of the line 1-2c so as to obtain rMS-pUV15-icl and rMS-pUV15. Shuttle plasmid rMS-pUV15-IG expressing ICL-green fluorescent protein (GFP) was constructed. rMS-pUV15-IG and MS 1-2c were used to infect the murine macrophages of the line RAW264.7, fluorescence microscopy was used to observe the expression of ICL-GFP. The expression of ICL in the MS swallowed by the macrophages was verified by RT-PCR and Western blotting. Another macrophages RAW264.7 were cultured and infected with rMS-pUV15-icl and rMS-pUV15 respectively. 0, 24, and 48 hours later macrophages were collected and the number of MS colonies was calculated. The interferon (IFN)-gamma and nitrogen oxide (NO) concentrations in the culture supernatants of macrophages infected by rMS-pUV15-icl and rMS-pUV15 were measured by ELISA and Griess assay respectively. The apoptotic rate of the macrophages was assayed by in situ TUNEL technique. RESULTS: Western blotting showed that the MTB ICL protein expression of the rMS-pUV15-icl was significantly higher than that of rMS-pUVI5. Fluorescence microscopy showed green fluorescence in the RAW264.7 cells infected with rMS-pUV15-IG, but not ion the RAW264.7 cells infected with MS 1-2c. 0 h after the infection of the macrophages there was not significant difference in the MS amount in the macrophages between the rMS-pUV15-isl and rMS-pUV15 groups, and 24 h and 48 h later the MS amounts of the rMS-pUV15-icl group were (32.78 +/- 2.90) x 10(3) and (23.33 + 2.34) x 10(3) respectively, both significantly higher than those of the rMS-pUV15 group [(14.67 +/- 2.45) x 10(3) and (2.28 +/- 0.25) x 10(3) respectively, both P < 0.01]. There were not significant differences in the concentrations of IFN-gamma and NO in the culture supernatants between the 2 groups (both P >0.05). 48 h after the infection the apoptotic rate of the rMS-pUV15-icl group was significantly lower than that of the rMS-pUV15 group (P <0.01). Conclusion MTB-ICL promotes the intracellular survival of MS. Suppressing the apoptosis of the host macrophage may be one of the important mechanisms involved in this increased intracellular survival.

[Therapeutic effects of granulysin/interleukin-12 recombinant M. smegmatis in a murine model of M. tuberculosis infection].

OBJECTIVE: To study the effects and mechanisms of recombinant Mycobacterium smegmatis (M. smegmatis) encoding human granulysin and murine interleukin-12 (IL-12) on murine M. tuberculosis infection. METHODS: Balb/c mice infected with M. tuberculosis were treated with normal saline, M. smegmatis, pZM03, recombinant M. smegmatis respectively. The numbers of viable bacteria in the lung and the spleen were counted. The levels of IL-12, IgG(2a) in serum and interferon-gamma (IFN-gamma) released from spleen lymphocytes stimulated with purified protein derivative (PPD) were detected with enzyme linked immunosorbent assay (ELISA). The expression of granulysin in tissue was detected with immunohistochemistry. Lungs and spleens were prepared for pathological analysis. RESULTS: The recombinant M. smegmatis group [(4.57 +/- 0.28) in lung, (3.47 +/- 0.25) in spleen] showed significantly reduced number of colony forming units (log CFU/g) compared with the control [(5.77 +/- 0.12) in lung, (4.66 +/- 0.18) in spleen], M. smegmatis [(5.62 +/- 0.14) in lung, (4.65 +/- 0.26) in spleen] and pZM03 [(5.04 +/- 0.22) in lung, (4.25 +/- 0.48) in spleen] group. The expression of granulysin in tissue, and increased level of IL-12 and IgG(2a) in serum were found in recombinant M. smegmatis group. IFN-gamma released from spleen lymphocytes stimulated with PPD in recombinant M. smegmatis group and pZM03 group was higher than that of other groups, but the difference between recombinant M. smegmatis group and pZM03 group was not significant. The pathological changes in lungs of the recombinant M. smegmatis group were localized, while those in the control group were extensive. Significant pathological changes were not found in the spleens of all groups. CONCLUSION: The recombinant M. smegmatis had immunotherapeutic effects, which were associated with a switch to Th1 response and the antibacterial activity of granulysin.

[Inhibitory effects of 10-23 deoxyribozyme targeting ICL gene on the expression of isocitrate lyase and the infection of Mycobacterium tuberculosis in macrophages].

OBJECTIVE: To investigate the inhibitory effects of the 10-23 deoxyribozyme (DRZ) targeting ICL gene on the expression of isocitrate lyase (ICL) and the survival of Mycobacterium tuberculosis in macrophages. METHODS: Five 10-23 DRZ targeting ICL genes (DZ1-DZ5) were designed according to the predicted secondary structure of Mycobacterium tuberculosis ICL mRNA. Their cleavage activity and specificity were identified in cell free conditions. Then Mycobacterium tuberculosis pretreated with DZ4 with or without subinhibitory concentration of isoniazid (INH) were used to infect THP-1 cells. The bacterial burden of the infected THP-1 cells was monitored at indicated times after infection. The effect of 10-23 DRZ on the growth of Mycobacterium tuberculosis in vitro was also assayed by plating Mycobacterium tuberculosis treated with INH alone or DZ4 plus INH on M7H10 agar directly. RESULTS: Four of the five designed 10-23 DRZ, DZ1, DZ3, DZ4 and DZ5 could cleavage ICL mRNA efficiently and specifically. Treating Mycobacterium tuberculosis with 5 micromol/L DZ4 plus subinhibitory concentration of INH decreased the expression of ICL dramatically, by 34.9% - 46.7% (10 microg/L INH, P < 0.01) or 21.9% - 36.9% (5 microg/L INH, P < 0.01) when compared with corresponding concentration of INH alone. The survival of Mycobacterium tuberculosis in THP-1 cells was decreased significantly when Mycobacterium tuberculosis was pretreated with 5 micromol/L DZ4 plus subinhibitory concentration of INH. 4 or 7 days after infection, the bacteria burden in macrophages was decreased from 126.5 x 10(4) CFU, 307.5 x 10(4) CFU to 54.6 x 10(4) CFU, 114.3 x 10(4) CFU (when 10 microg/L INH used) or from 133.0 x 10(4) CFU, 325.4 x 10(4) CFU to 71.7 x 10(4) CFU, 174.4 x 10(4) CFU (when 5 microg/L INH used). 10-23 DRZ showed no obvious effect on the growth of Mycobacterium tuberculosis in M7H10 agar. CONCLUSIONS: INH at the subinhibitory concentration can improve the entry of 10-23 DRZ in Mycobacterium tuberculosis. In the presence of subinhibitory concentration of INH, 10-23 DRZ targeting ICL gene can strongly inhibit the expression of ICL and decrease the survival of Mycobacterium tuberculosis in macrophages.

Mutant spectrum of dengue type 1 virus in the plasma of patients from the 2006 epidemic in South China.

The aim of the present study was to explore the mutant spectrum of dengue type 1 virus (DENV-1) within individuals during the 2006 dengue epidemic in South China. A 513-bp fragment including most of domain III of the envelope (E) gene was amplified directly from clinical samples, then cloned and sequenced. A total of 89 clones from six patients (range 11-17 clones per patient) were sequenced. Genetic diversity was calculated using MEGA 4 package. The total number of nucleotide mutations was 113 (3.7%) within the sequenced 513-bp E gene, with a range of 15 (3%) to 24 (4.7%) within individual viral populations, harboring more non-synonymous than synonymous mutations. The extent of sequence diversity varied among patients, with the mean diversity ranging from 0.19% to 0.32%, and the mean pairwise p-distance ranging from 0.34% to 0.65%. No genome-defective virus was detected in any clone in this study. Purifying selection may be the main driving force for the intrahost evolution: the mean dN/dS ratio was 0.532. Our findings contribute to the understanding of the genetic variation of DENV-1 in South China.

[Expression of human granulysin in murine macrophages and its effects on cell damage and apoptosis].

AIM: To construct an eukaryotic expression vector pBudCE4.1/GLS encoding human granulysin(GLS) derived from activated CTLs and observe its effects on cell damage and apoptosis when expressed in macrophages of various murine germ lines. METHODS: The gene sequence coding GLS carried on pEGFP-C1/GLS was subcloned into pBudCE4.1 plasmid and then transfected into different murine macrophages. The expression of GLS was detected by RT-PCR and immunocytochemical staining. The impairment and apoptosis of the host cells was assesed by measuring LDH in culture media and fluorescent staining of nuclear DNA, respectively. RESULTS: The pBudCE4.1/GLS recombinant containing accurate ORF of GLS was obtained and successfully expressed in the target cells at 48 h after transfection. No obvious effects on cell damage and apoptosis was detected during this course. CONCLUSION: The gene coding human GLS can be expressed in murine macrophages. The expressed product has no obvious effects on cell damage and apoptosis.