Mechanisms of active fraction combination from Liuwei Dihuang Decoction(LW-AFC) on long-term potentiation impairment in vivo

OBJECTIVE Liuwei Dihuang Decoction(LW)-active fraction combination(LW-AFC,consist of 3 fractions polysaccharide,LWB-B;glycoside,LWD-b;oligosaccharide,CA-30)is extracted from LW,it is effective for the treatment of kidney yin deficiency in many animal models.This study evaluated the effects and mechanisms of LW-AFC and the active fractions on corticosterone(Cort)-induced long-term potentiation(LTP)impairment in vivo.METHODS LTP was used to evaluate the synaptic plasticity.LW-AFC was orally administered for seven days.The active fractions were given by either chronic administration(ig,ip,7 d)or single administration(icv,ig,ip).Cort was injected subcutaneously 1h before the high-frequency stimulation(HFS)to induce LTP impairment.Moreover,in order to research on the possible effective pathways,an antibiotic cocktail and an immunosuppressant were also used.RESULTS Chronic administration(ig)of LW-AFC and its three active fractions could ameliorate Cort-induced LTP impairment.Single administration(icv,ig,ip)of any of the active fractions had no effect on Cort-induced LTP impairment,while chronic administration(ig,ip)of LWB-B or LWD-b showed positive effects against Cort.Interestingly,CA-30 only showed protective effects via ig administration,and there was little effect when CA-30 was administered ip In addition,when the intestinal microbiota was disrupted by application of the antibiotic cocktail,CA-30 showed little protective effects against Cort.The effects of LW-AFC were also abolished when the immune function was inhibited.In the hippocampal tissue,Cort treatment increased Cort and glutamate,and LW-AFC could inhibit the Cort-induced elevation of Cort and glutamate;there was little change in D-serine in Cort-treated animals,but LW-AFC could increase the D-serine levels.CONCLUSION LW-AFC and its three active fractions could ameliorate Cort-induced LTP impairment.Their protective effects are unlikely by a direct way,and immune modulation might be the common pathway.CA-30 could protect LTP from impairment via modulating the intestinal microbiota.Decreasing Cort and glutamate and increasing D-serine in the Cort-treated animals'hippocampal tissue might be one of the mechanisms for the neural protective effects of LW-AFC.Further study is needed to understand the underlying mechanisms.

Screening of active fractions from Radix of Actinidiae chinensis in vitro

Objective Radix of Actinidiae chinensis,a medicinal plant used in China,is the dry root of Actini-diaceae plant and has been extensively employed to treat cancers of various organs,including the lung,liver and digestive system.However,up to now,its active antitumor and antiviral fractions remain unclear.The main purpose of this study is to identify the antitumor and antiviral sites of Radix of Actinidiae chinensis,which provides evidences for its further development.Methods Radix of Actinidiae chinensis was extracted by the refluxing sequentially with acetidin,ethanol and water,followed by the column chromatography and thin layer chromatography.The antitumor effects on Bel-7402,SW-620 and MDA-MB-231 tumor cells were investigated to screen the active antitumor sites by cell inhibition,the growth curve and the apoptosis staining.Meanwhile,to screen the active anti-hepatovirus fractions,the cell growth and the secretion of HBsAg and HBeAg in HepG2.2.15 cells were evaluated by the MTT test and enzyme-linked immunosorbent assay respectively.Results The acetidin fraction Y(Y1+Y2),the ethanol fraction A(A1+A3+A4) and B(A1+A4+A6),and the fraction compound C(A1+A4+Y1) have strong inhibitive effects on Bel-7402,SW-620 and MDA-MB-231 tumor cell lines.Moreover,the tumor cell apoptosis could be induced by the ethanol fraction B and the fraction compound C.In HepG2.2.15 cells,the treatment indexes of the acetidin fraction Y,the ethanol fraction A and the fraction compound C all exceeded 2 on the secretion of HBsAg,indicating the suppre-ssive effects of them on hepatitis B virus.The fraction yields of A,B and C exceeded 50%(60.28%,54.35% and 62.64% respectively),while that of Y did not(17.7%).Conclusion The ethanol fraction B and the fraction compound C are the antitumor sites of Actinidiae chinensis Radix,while the ethanol fraction A and the fraction compound C are its antiviral sites.

Experimental Study on the Dependency of Ice Nucleation Active Surface Site Density on ATD Aerosol Size

In light of the percentage of Earth’s cloud coverage, heterogeneous ice nucleation in clouds is the most important global-scale pathway. More recent parameterizations of ice nucleation processes in the atmosphere are based on the concept of ice nucleation active surface site density (ns). It is usually assumed that ns is independent of time and aerosol size distribution, i.e. that the surface properties of aerosols of the same species do not vary with size. However, the independence of ns on aerosol size for every species has been questioned. This study presents the results of ice nucleation processes of ATD laboratory-generated aerosol (particle diameters of 0 - 3 μm). Ice nucleation in the condensation mode was performed in a Dynamic Filter Processing Cham- ber at temperatures of -18°C and -22°C, with a saturation ratio with respect to water of 1.02. Results show that ns increased by lowering the nucleation temperature, and was also dependent on the particle size. The ns of particles collected on the filters, after a 0.5 μm D50 cut-off cyclone, resulted statistically higher with respect to the values obtained from the particles collected on total filters. The results obtained suggest the need for further investigation of ns dependence of same composition aerosol particles with a view to support weather and climate predictions.

Remote estimation of the fraction of absorbed photosynthetically active radiation for a maize canopy in Northeast China

Aims accurate remote estimation of the fraction of absorbed photosynthetically active radiation(fAPAR)is essential for the light use efficiency(LUE)models.Currently,one challenge for the LUE models is lack of knowledge about the relationship between fAPAR and the normalized difference vegetation index(NDVI).Few studies have tested this relationship against field measurements and evaluated the accuracy of the remote estimation method.this study aimed to reveal the empirical relationship between NDVI and fAPAR and to improve algorithms for remote estimation of fAPAR.Methods to investigate the method of remote estimation of fAPAR seasonal dynamics,the CASA(Carnegie-ames-stanford approach)model and spectral vegetation indices(VIs)were used for in situ measure-ments of spectral reflectance and fAPAR during the growing season of a maize canopy in Northeast China.Important Findingsthe results showed that the fAPAR increased rapidly with the day of year during the vegetative stage,it remained relatively stable at the stage of reproduction,and finally decreased slowly during the senescence stage.In addition,fAPAR green[fAPAR_(green)=fAPAR_(green) -fAPAR_(green) LAI_(max))]showed clearer seasonal trends than fAPAR.the NDVI,red-edge NDVI,wide dynamic range vegetation index,red-edge position(REP)and REP with sentinel-2 bands derived from hyperspectral remote sensing data were all significantly positively related to fAPAR green during the entire growing season.In a comparison of the predictive performance of VIs for the whole growing season,REP was the most appropriate spectral index,and can be recommended for monitoring seasonal dynamics of fAPAR in a maize canopy.

Tropical forest canopies and their relationships with climate and disturbance： results from a global dataset of consistent field-based measurements

Background： Canopy structure, defined by leaf area index （LAI）, fractional vegetation cover （FCover） and fraction of absorbed photosynthetically active radiation （fAPAR）, regulates a wide range of forest functions and ecosystem services. Spatially consistent field-measurements of canopy structure are however lacking, particularly for the tropics. Methods： Here, we introduce the Global LAI database： a global dataset of field-based canopy structure measurements spanning tropical forests in four continents （Africa, Asia, Australia and the Americas）. We use these measurements to test for climate dependencies within and across continents, and to test for the potential of anthropogenic disturbance and forest protection to modulate those dependences. Results： Using data collected from 887 tropical forest plots, we show that maximum water deficit, defined across the most arid months of the year, is an important predictor of canopy structure, with all three canopy attributes declining significantly with increasing water deficit. Canopy attributes also increase with minimum temperature, and with the protection of forests according to both active （within protected areas） and passive measures （through topography）. Once protection and continent effects are accounted for, other anthropogenic measures （e.g. human population） do not improve the model. Conclusions： We conclude that canopy structure in the tropics is primarily a consequence of forest adaptation to the maximum water deficits historically experienced within a given region. Climate change, and in particular changes in drought regimes may thus affect forest structure and function, but forest protection may offer some resilience against this effect.

Study on Therapeutic Mechanism of Anti-Rheumatism Effect of Siegesbeckia Pubescens

Objective: To explore the mechanism of anti-rheumatic effect of the active fraction of Siegesbeckia pubescens (AFSP). Methods: Adjuvant arthritis (AA) model of rat was produced to observe the effect of AFSP on lymphocyte proliferation, interleukin-1 and -2 (IL-1,-2) activity, pathologic section of ankle joint, and analgesic effect, in model rat. Results: AFSP could reduce the inflammatory pathologic response of ankle joint. It has good analgesic effect, the analgesic rate being 65%. AFSP could also strengthen T-lymphocyte proliferation, promote IL-2 activity and inhibit IL-1 activity. Compared with the control group, the difference was significant (P<0.01). Conclusion: By means of regulating the immune function of organism, AFSP could improve the local pathologic response to antagonize against rheumatism, therefore, it is an effective anti-rheumatism herbal medicine.

Synergistic Antimicrobial Activity of Berberine Hydrochloride, Baicalein and Borneol against Candida albicans

Objective To determine the synergistic effects of berberine hydrochloride, baicalein,and borneol in different combinations on Candida albicans. Methods The broth microdilution method was used to determine the minimal inhibitory concentration（MIC） and minimal bactericidal concentration（MBC） of the three agents, and the checkerboard method was simultaneously used to determine the MIC and fractional inhibitory concentration index（FICI） of the combination of three antimicrobial agents to study their extracorporeal effects. Results Berberine hydrochloride was the most potent inhibitor of C. albicans（MIC and MBC of 0.160 and 0.640 mg/mL）, followed by borneol（MIC and MBC of 0.320 and 0.640 mg/mL） and baicalein（MIC and MBC of 1.28 and 20.48 mg/mL）. Moreover, the antifungal effect of the combination was significantly stronger than that tested alone. Further in vivo study showed that the mortality rate of tainted mice reduced over 50% compared with the control group. Conclusion The results of experiments in vitro and in vivo indicate the synergistic effect of the combination of three antimicrobial agents on C. albicans, which can make reference for the future clinical treatment.