[Analysis of HONO Concentration and Source in Typical Rural Area of North China].

Nitrous acid (HONO) is easily photolyzed with the production of·OH, which plays an important role in the formation of regional secondary pollution. In China, research of HONO observation is concentrated mainly in urban areas and is rarely reported in rural areas. In our study, a one-month HONO field observation was conducted at the Station of Rural Environment, Chinese Academy of Sciences (Dongbaituo Village, Wangdu County, Hebei Province) in November 2017 using the long path absorption photo meter (LOPAP). The concentration, variety characteristics, and budget of HONO was studied. During the observation period, HONO exhibited pronounced diurnal variation with low concentrations in the day and high concentration in the evening. The highest concentration at night was about 3.70×10-9, and the lowest concentration at noon was about 0.10×10-9, indicating the presence of a strong source of HONO in rural areas. The CO concentration increased significantly before and after heating, whereas the HONO concentration did not change significantly, indicating that heating combustion contributed less to HONO, Direct emission of motor vehicles at night contributed 23.20% and 31.20% to HONO in polluted and clean weather conditions, respectively, indicating the presence of strong sources of HONO in polluted weather conditions. The average formation rate of HONO at night from homogeneous reaction of·OH and NO could reach 0.40×10-9 h-1, which is 0.67 times higher than that of heterogeneous reaction of NO2 (0.24×10-9 h-1), indicating that the homogeneous reaction of·OH and NO is the main source of HONO at night. HONO has a strong unknown source in the daytime with an intensity reaching 1.37×10-9 h-1, which contributes about 50% to HONO.

Rapid Construction of Full-length cDNA Clones of Tobacco Mosaic Virus and the Infectivity Assay of Its in Vitro Transcript.

The full-length cDNA of tobacco mosaic virus faba bean isolate (TMV-B) was amplified with RT-PCR in which T7 promoter sequence was added in the 5' terminus of its upstream primer, so that full-length cDNA was put directly under the control of a T7 promoter. The cDNA was cloned into plasmid pT7Blue and linear DNA was got by digesting the recombinant with KpnI or KpnI and PstI. Using these linear DNA and full-length PCR product as templates, respectively, their in vitro transcripts were inoculated to Nicotiana tabacum and Chenopodium amaranticolor. All of the transcripts had infectivity and produced symptoms similar to that of wild TMV. It was found that transcripts of the full-length PCR product had higher infectious efficiency than those of linear DNA.

Emergence of a new satellite RNA from cucumber mosaic virus isolate P1.

The cucumber mosaic virus (CMV) isolate P1 caused very mild symptoms on many plant species. After serial passages by mechanical inoculation over five years, CMV P1 caused severe symptoms on several tobacco cultivars and tomato. A specific band of approximately 0.3 kb in length was amplified by RT-PCR with primers synthesized based on reported CMV satellite RNA (satRNA) sequences. Sequence analysis showed there were two satRNAs (Sat-P1-1 and Sat-P1-2). Sat-P1-1 contained 335 nucleotides, and Sat-P1-2 contained 394 nucleotides. These two satRNAs shared 64% overall nucleotide sequence homology, and differences between the two satRNAs included mutations as well as deletions. Sat-P1-1 was identical to a satRNA (Z96099) reported in 1995 in CMV P1. Based on differences in the sequence and secondary structure between these two satRNAs, we conclude that Sat-P1-2 represents the emergence of a new satellite (necrotic satellite) from attenuated satRNA populations. The possible effect of the emergence of this new satRNA is discussed.

Effects of interleukin-1β on mineralization potential of dental pulp stem cells / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the effects of pro-inflammatory cytokine interleukin-1β (IL-1β) on mineralization potential of dental pulp stem cells (DPSC).</p><p><b>METHODS</b>Rat DPSC were cultured in vitro and randomly divided into three groups, IL-1β (10 µg/L), osteogenic inductive medium and non-osteogenic inductive medium. After 3, 7, and 12 days of treatment, the cultures were evaluated for cell proliferation and calcium deposit. Real-time polymerase chain reaction was used to detect the gene expression levels of osteocalcin (OC), bone sialoprotein (BSP), dentin sialophosphoprotein (DSPP) and dentin matrix protein 1 (DMP-1). In vivo test, after 3 day's treatment with IL-1β, the cell-scaffold complexes were implanted subcutaneously in mice for 8 weeks. Histological analysis was performed to evaluate hard tissue formation.</p><p><b>RESULTS</b>In vitro test, after 3-day's treatment, IL-1β improved cell proliferation to 137.22 DNA µg/L and cell viability becomes (97.12 ± 7.18)% of control. The gene expression levels of OC, BSP, DSPP and DMP-1 are (378.19 ± 16.22)%, (427.12 ± 18.22)%, (247.19 ± 10.11)% and (198.29 ± 10.23)% respectively. The results of IL-1β's group was notable increased compared with non-osteogenic induction medium and the statistical differences are significant. IL-1β induced the odontogenic differentiation of DPSC. However, these effects tended to continuously decrease with treatment time. Histological analysis demonstrated that in the group treated with IL-1β hard tissue was markedly formed in vivo.</p><p><b>CONCLUSIONS</b>IL-1β may induce the mineralization of DPSC and play an important role in host defenses and tissue repair.</p>

Construction of human bone morphogenetic protein-7 gene fluorescent eukaryotic cell expression vector and test of bioactivity in vitro / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To construct fluorescent eukaryotic cell expression vector with human bone morphogenetic protein-7 (hBMP-7) gene and to transfect mouse stromal cell line W-20-17 to detect the bioactivity of pEGFP-hBMP-7 in vitro.</p><p><b>METHODS</b>pEGFP-hBMP-7 plasmid was constructed by subcloning technique and identified by enzyme cutting and electrophoresis. W-20-17 cells were transfected with pEGFP-hBMP-7 by means of lipofectamine-2000 media methods. Transfection efficiency and gene expression were evaluated by fluorescent microscopy. ALP, von Kossa and osteocalcin (OC) were tested to determined the phenotypes of osteoblast.</p><p><b>RESULTS</b>After 48 hours, the gene transfection efficiency was 40%. Based on GFP and immunofluorescence of pEGFP-hBMP-7, there was the expression of aim gene. After gene transfection, there were not significant different of cell morphology feature and cell proliferation. ALP activity, the number of calcium nodules and the expression of OC increased.</p><p><b>CONCLUSIONS</b>pEGFP-hBMP-7 with bioactivity was constructed, which could induce W-20-17 cells to differentiate to osteoblasts.</p>

Identification and isolation of human dental pulp stem cells / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To isolate and cultivate human dental pulp stem cells (DPSCs).</p><p><b>METHODS</b>Pulp tissue was removed from healthy young human teeth extracted for orthodontic purposes. The pulp was digested by Type I collagenase and dispase. Then single-cell suspensions were obtained by filter and cultivated. The clones were identified by expression of STRO-1. Under the conditions of inducement, clones were identified by activity of alkaline phosphatase (ALP), formation of mineralized nodule and expression of dentin sialoprotein (DSP), and by Oil Red-O dyeing and expressing of PPARr2.</p><p><b>RESULTS</b>The clones had positive expression of STRO-1. When stimulated to differentiation, these cells took on dramatically high activity of ALP, had the ability of mineralization and expressed DSP. These cells also had ability to trans-differentiate into adipocytes.</p><p><b>CONCLUSION</b>There are stem cells in human dental pulp tissues, which can be isolated and cultivated.</p>

Osteogenic differentiation of synovial mesenchymal stem cells in vitro / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the potential of synovial mesenchymal stem cells (SMSC) in osteogenic differentiation.</p><p><b>METHODS</b>SMSC were obtained by limited dilution method and expanded to culture in 25-milliliter flasks. The attached cells were treated with inductive medium containing dexamethasone, glycerophosphate and vitamin C at 3rd passage SMSC. The mineralized nodule was stained by Von Kossa method. The expression of ALP and osteopontin were detected by histochemical, immunohistological staining technique, respectively, while the expression of cbfa1 mRNA by RT-PCR.</p><p><b>RESULTS</b>Pure SMSC which were of spindle shape and star shape, uniform in size, could be induced to pleomorphism osteoblast in vitro, which were intensive positive in ALP and osteopontin. The expression of cbfa1 mRNA were also verified by RT-PCR and the polygonal cells formed nodular structure at 4 weeks. All these were coincident with the characters of osteoblast.</p><p><b>CONCLUSION</b>SMSC can be purified and induced into osteoblast in vitro.</p>