[Effects of Enhanced Ultraviolet B Irradiation on Photosynthetic and Antioxidant System of Sorghum Seedlings].

The UV-B radiation on the surface of our planet has been enhanced due to gradual thinning of ozone layer. The change of solar spectrum UV-B radiation will cause damage to all kinds of terrestrial plants at certain degree. In this paper, taking breeding sorghum (Sorghum bicolor (L.Moench))variety Longza No.5 as sample, 40 µW·cm-2 UV-B radiation treatment was conducted on sorghum seedlings at two-leaf and one-heart stage and different time courses; then after a 2 d recovering, photosynthetic parameters were measured with a photosynthetic apparatus; the activities of antioxidant enzymes were detected as well. Our results revealed that, as the dosages of UV-B increasing, leaf browning injury was aggravated, plants dwarfing and significantly were reduced fresh weight and dry weight were observed; anthocyanin content was significantly increased; chlorophyll and carotenoid content significantly were reduced and net photosynthetic rate and chlorophyll fluorescence parameters were decreased. Meanwhile, with the increase in UV-B dosages, stomatal conductance, intercellular CO2 concentration and transpiration rate showed "down - up - down" trend; the activities of SOD and GR presented "down - up" changes; activities of POD and CAT demonstrated "down - up - down", and APX, GPX showed an "up - down - up" pattern. It is worth to note that, under the four-dose treatment, a sharp decline in net photosynthesis in sorghum seedlings was observed at 6 h UV-B treatment (equals to 2.4 J·m-2), and an obvious turning point was also found for other photosynthetic parameters and activities of antioxidant enzymes at the same time point. In summary, the results indicated that the enhanced UV-B radiation directly accounted for the damages in photosynthesis system including photosynthetic pigment content, net photosynthetic rate and chlorophyll fluorescence parameters of sorghum; the antioxidant system showed different responses to UV-B radiation below or above 6 h treatment: ASA-GSH cycle was more sensitive to low-dose UV-B radiation, while high-dose UV-B radiation not only undermined the photosynthesis system, but also triggered plant enzymatic and non-enzymatic antioxidant systems, resulting in leaf browning and necrosis,biomass accumulation reduction, plant dwarfing and even death.

Intracellular chloride channel protein CLIC1 regulates macrophage function through modulation of phagosomal acidification.

Intracellular chloride channel protein 1 (CLIC1) is a 241 amino acid protein of the glutathione S transferase fold family with redox- and pH-dependent membrane association and chloride ion channel activity. Whilst CLIC proteins are evolutionarily conserved in Metazoa, indicating an important role, little is known about their biology. CLIC1 was first cloned on the basis of increased expression in activated macrophages. We therefore examined its subcellular localisation in murine peritoneal macrophages by immunofluorescence confocal microscopy. In resting cells, CLIC1 is observed in punctate cytoplasmic structures that do not colocalise with markers for endosomes or secretory vesicles. However, when these macrophages phagocytose serum-opsonised zymosan, CLIC1 translocates onto the phagosomal membrane. Macrophages from CLIC1(-/-) mice display a defect in phagosome acidification as determined by imaging live cells phagocytosing zymosan tagged with the pH-sensitive fluorophore Oregon Green. This altered phagosomal acidification was not accompanied by a detectable impairment in phagosomal-lysosomal fusion. However, consistent with a defect in acidification, CLIC1(-/-) macrophages also displayed impaired phagosomal proteolytic capacity and reduced reactive oxygen species production. Further, CLIC1(-/-) mice were protected from development of serum transfer induced K/BxN arthritis. These data all point to an important role for CLIC1 in regulating macrophage function through its ion channel activity and suggest it is a suitable target for the development of anti-inflammatory drugs.

Photo-Controlled Nano-Supramolecular Size and Reversible Luminescent Behaviors Based on Cucurbit[7]uril Cascaded Assembly.

Supramolecular luminescent material with switchable behavior and photo-induced aggregation with emission enhancement is a current research hot spot. Herein, a size-tunable nano-supramolecular assembly with reversible photoluminescent behavior was constructed by noncovalent polymerization of diarylethene-bridged bis(coumarin) derivative (DAE-CO), cucurbit[7]uril (CB[7]), and ß-cyclodextrin-grafted hyaluronic acid (HACD). Benefiting from the macrocyclic confinement effect, the guest molecule DAE-CO was included into the cavity of CB[7] to give enhanced fluorescence emission of the resulting DAE-CO⊂CB[7]2 with longer lifetime at 432 nm to 1.43 ns, thereby further enhancing fluorescence output and lifetime (1.46 ns) when further assembled with HACD, compared with the free DAE-CO (0.95 ns). In addition, DAE-CO, DAE-CO⊂CB[7]2, and DAE-CO⊂CB[7]2&HACD all possessed characteristics of aggregation-induced emission and reversible photo-switched structural interconversion, exhibiting an obvious photophysical activation phenomenon of self-aggregation into larger nanoparticles with increase in fluorescence emission intensity, lifetime, and size after irradiation, which could be increased step by step with the alternating irradiation of 254 nm (5 min) or >600 nm (30 s) repeated 7 times. These supramolecular assemblies were successfully used in the tumor cells' targeted imaging and anti-counterfeiting because of the capability of HACD for recognizing specific receptors overexpressed on the surface of tumor cells and the excellent photo-regulated switch ability of DAE-CO, providing an approach of constructing photo-induced emission-enhanced luminescent materials.

Design, synthesis and in vitro activities on anti-platelet aggregation of 4-methoxybenzene-1,3-isophthalamides.

On the purpose of searching for the structure-activity relationship (SAR) and obtaining novel anti-platelet drugs, 41 4-methoxybenzene-1,3-isophthalamides have been described the synthesis process and in vitro activities on anti-platelet aggregation. The target compounds have been classified into four series: series 1 (ortho-substituted phenyl: 1a-1j), series 2 (meta-substituted phenyl: 2a-2k), series 3 (para-substituted phenyl: 3a-3l) and series 4 (aromatic of no substituted group and aromatic heterocyclic substituted groups: 4a-4h). The chemical structures of the target compounds were confirmed by MS, IR, (1)H NMR, and their in vitro activities on anti-platelet aggregation were tested and assessed by using Born test. The result showed that thirteen compounds 1c, 1d, 1i, 1j, 2g, 3a, 3c, 3d, 3f, 3h, 3l, 4b and 4c have superior anti-platelet aggregation activities than the reference drug Picotamide.

The CFP-10/ESAT-6 complex of Mycobacterium tuberculosis potentiates the activation of murine macrophages involvement of IFN-gamma signaling.

Secretory antigen of Mycobacterium tuberculosis, culture filtered protein 10(CFP-10) and early secreted antigenic target 6 kDa protein (ESAT-6) are closely correlated with immunogenicity and virulence of Mycobacterium tuberculosis. But the mechanism of its immunogenicity and virulence is still unclear. In this study, we investigated the influence of the CFP-10/ESAT-6 complex on production of IL-12 and nitric oxide (NO) produced by the ANA-1 macrophage cell line. Preincubation with the complex in a time-dependent manner significantly enhanced production of NO and IL-12 released from ANA-1 cells following IFN-gamma stimulation. In addition, the complex up-modulated expression level of IFN-gammaR1 on surface of the macrophages. Furthermore, the effect of the complex on production of IL-12 and NO in ANA-1 cells was suppressed by AG490, a selective inhibitor of JAK/STAT pathway. These data suggest that in the presence of IFN-gamma, CFP-10/ESAT-6 complex represents a new immunogenicity and protective factor that may be, at least partly, due to up modulation of IFN-gammaR1 expression and activation of JAK/STAT pathway.

[Alleviation of salt stress during maize seed germination by presoaking with exogenous sugar].

The maize variety Kenyu 6 was used to study the effects of exogenous glucose (Glc) and sucrose (Suc) on salt tolerance of maize seeds at germination stage under 150 mmol · L(-1) NaCl treatment. Results showed that under salt stress condition, 0.5 mmol · L(-1) exogenous Glc and Suc presoaking could promote seed germination and early seedling growth. Compared with the salt treatment, Glc presoaking increased the shoot length, radicle length and corresponding dry mass up to 1.5, 1.3, 2.1 and 1.8 times, and those of the Suc presoaking treatment increased up to 1.7, 1.3. 2.7 and 1.9 times, respectively. Exogenous Glc and Suc presoaking resulted in decreased levels of thiobarbituric acid reactive substances (TBARS) and hydrogen peroxide (H2O2) content of maize shoot under salt stress, which were lowered by 24.9% and 20.6% respectively. Exogenous Glc and Suc presoaking could increase the activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), glutathione peroxidase (GPX), glutathione reductase (GR) and induce glucose-6-phosphate dehydrogenase (G6PDH) activity of maize shoot under salt stress. Compared with the salt treatment. Glc presoaking increased the activity of SOD, APX, GPX, GR and G6PDH by 66.2%, 62.9%, 32.0%, 38.5% and 50.5%, and those of the Suc presoaking increased by 67.5%, 59.8%, 30.0%, 38.5% and 50.4%, respectively. Glc and Suc presoaking also significantly increased the contents of ascorbic acid (ASA) and glutathione (GSH), ASA/DHA and GSH/GSSG. The G6PDH activity was found closely related with the strong antioxidation capacity induced by exogenous sugars. In addition, Glc and Suc presoaking enhanced K+/Na+ in maize shoot by 1.3 and 1.4 times of water soaking salt treatment, respectively. These results indicated that exogenous Glc and Suc presoaking could improve antioxidation capacity of maize seeds and maintain the in vivo K+/Na+ ion balance to alleviate the inhibitory effect of salt stress on maize seed germination.

[The construction and expression of Rv3872 as a member of virulent protein secret system from Mycobacterium tuberculosis in Bacillus Calmette-Guerin].

AIM: To construct, express and identify a recombinant prokaryotic expression vector pET-3872 carrying Rv3872 of Mycobacterium tuberculosis H37Rv strain, and to construct the recombinant Bacillus Calmette-Guerin (rBCG) strain expressing Rv3872 (PE35)of Mycobacterium tuberculosis H37Rv strain. METHODS: The Rv3872 gene was amplified by PCR from Mycobacterium tuberculosis H37Rv strain and cloned into prokaryotic expression vector pET32a(+). The recombinant plasmid pET-3872 was sequenced and transformed into E.coli BL21(DE3), and was induced with IPTG to express a 35 kD fusion protein, which was confirmed as His-Rv3872 by Western blot. The expression product was purified and the new Zealand rabbits were immunized. Rv3872 was amplified by PCR and cloned into E.coli-Mycobacteria shuttle vector pMV361. The recombinant vector was named as pMV-3872, and then pMV-3872 was transformed the to BCG via electroporation, the recombinant BCG-3872 strain. The PE35 protein expression of BCG-3872 was induced with heat shock reaction. Then BCG-3872 culture supernatant and bacterial precipitation were collected respectively and analyzed by Western blot. RESULTS: A recombinant fused expression vector pET-3872 was constructed and His-3872 protein was confirmed by Western blot. BCG-3872 strain was constructed and Western blot confirmed the presenle of the PE35 protein in the supernatant of BCG-3872 strain culture. CONCLUSION: The prokaryotic expression vector pET-3872 was constructed, and the 35 kD fusion protein His-3872 was expressed and purified successfully, which provides a tool for further functional study of the Rv3872 . The recombinant BCG strain expressing PE35 protein, BCG-3872 strain, was constructed successfully, which facilitates further study on BCG-3872 immune function.

[Progress in electricity generation from biomass using microbial fuel cell MFC)].

By applying bacteria as anodic catalyst, microbial fuel cell (MFC) can directly convert biomass energy into electrical energy, provided a new way for biomass utilization. Previous studies showed that the substrates and their concentration substantially affected performance of MFC. High power output was obtained when simple organic such as volatile fatty acids (VFA), alcohols or glucose was used as substrate. However, physical, chemical or even biological pretreatment methods were needed when substrate was complex organic. Addition of simple organic as co-substrate was also demonstrated to be an efficient way for refractory compounds degradation in MFC. Using biomass as substrates, MFC will be applied in area such as bioenergy recovery from wastewater, power supply in outfield and biosensors.