Expression of the Phycoerythrin Gene of Gracilaria lemaneiformis (Rhodophyta) in E. coli and Evaluation of the Bioactivity of Recombinant PE

Phycoerythrin (PE) is one of the most important proteins involved in light capturing during photosynthesis in red algae. Its potential biological activities had gained wide concerns. In the present study, tumor cytotoxic and hydroxyl radical assay were preformed to detect the bioactivity of recombinant PE. Recombinant plasmids pGEX-PE and pBGL were transformed into E.coli BL21 to make two recombinant strains BEX (pGEX-PE) and BGL (pBGL). PE expressing in BEX (pGEX-PE) was validated by SDS-PAGE and Western blotting analysis. SDS-PAGE analysis indicated that the PE-GST fusion protein was mostly inclusion bod- ies. Specific expression of PE was confirmed by Western blotting analysis. The recombinant E. coli BEX (pGEX-PE) cells were col- lected and sonicated. The supernatants were reserved for the tumor cytotoxic experiments. The result of tumor cytotoxic assay indi- cated that the supernatants containing PE had the activity of inhibiting the growth of Hela cells and with the increase of protein con- centration, the inhibiting rate increased from 37.31% to 63.26%, which showed significant difference from the control. Hydroxyl radical scavenging effect was tested with supernatants of BEX (pGEX-PE) and BGL (pBGL) cell lysates treated with sonication and heating. For the sonication samples, the scavenging rates of the supernatants of BEX (pGEX-PE) and BGL (pBGL) cell lysates were significantly higher than the negative control BL21(pGEX-4T) (P<0.02), and the scavenging rates increased slowly following the increase of the protein content. For the heating samples, except for the 0.2 mg mL-1 BGL (pBGL) products, the scavenging effects of the supernatants of BEX (pGEX-PE) and BGL (pBGL) cell lysates were stronger than that of negative control BL21(pGEX-4T). However, the effect intensity was not positively correlated with the increase of the protein concentration. Though a partially de- creased hydroxyl radical scavenging activity was led by heating, the biological activity was still retained and conspicuous. This re- search showed that phycoerythrin protein expressing in E. coli has the potential medical and sanitarian value.     

新疆强震活动与环境因子预报

本文运用新疆历史地震资料,分析了该地区的强震时空分布及地震活跃周期和活动图象,并探讨了强震活动与空间环境因子的关系,这无疑对新疆强震活动趋势分析和该地区强震中长期预报具有较重要的意义。     

Precursory seismicity of the 1994 eruption of Popocatépetl Volcano,Central Mexico

Popocatépetl Volcano is located in the central Mexican Volcanic Belt, within a densely populated region inhabited by over 20 million people. The eruptive history of this volcano indicates that it is capable of producing a wide range of eruptions, including Plinian events. After nearly 70 years of quiescence, Popocatépetl reawakened in December 21, 1994. The eruptive activity has continued up until the date of this submission and has been characterized by a succession of lava dome growth-and-destruction episodes, similar to events that have apparently been typical for Popocatépetl since the fourteenth century. In this regime, the episodes of effusive and moderately explosive activity alternate with long periods of almost total quiescence. In this paper we analyze five years of volcano-tectonic seismicity preceding the initial eruption of the current episode. The evolution of the V-T seismicity shows four distinct stages, which we interpret in terms of the internal processes which precede an eruption after a long period of quiescence. The thermal effects of a magma intrusion at depth, the fracturing related to the slow development of magma-related fluid pathways, the concentration of stress causing a protracted acceleration of this process, and a final relaxation or redistribution of the stress shortly before the initial eruption are reflected in the rates of V-T seismic energy release. A hindsight analysis of this activity shows that the acceleration of the seismicity in the third stage asymptotically forecast the time of the eruption. The total seismic energy release needed to produce an eruption after a long period of quiescence is related to the volume of rock that must be fractured so imposing a characteristic threshold limit for polygenetic volcanoes, limit that was reached by Popocatépetl before the eruption.     

羌塘盆地新构造活动与环境地质效应

本文将羌塘盆地新生代构造运动划分为三个阶段:古近纪为剥蚀、夷平和地壳加厚阶段;中新世为强烈挤压、褶皱阶段;上新世-全新世为高原缓慢整体抬升阶段。羌塘盆地的环境变迁和地质灾害与新生代构造活动密切相关。本区的强烈隆起、半荒漠化、沙尘暴、山洪、泥石流、冰川崩塌和雪崩、地震等均受新构造活动控制。     

最大熵谱法在华北地震活动幕式结构分析中的应用

应用定性和定量相结合的方法对华北地区第三、第四活动期Ｍ３≥６地震进行幕式结构分析，发现两个活动期的时间进程、应变释放的图象方面比较相似，由此推断第四活动期应变能大释放阶段已过、目前处于调整阶段。估计第四活动期可能持续到２０２０年前后。     

Origin and evolution of geothermal fluids from Las Tres Vírgenes and Cerro Prieto fields,Mexico – Co-genetic volcanic activity and paleoclimatic constraints

Major and trace elements, noble gases, and stable (δD, δ¹⁸O) and cosmogenic (³H, ¹⁴C) isotopes were measured from geothermal fluids in two adjacent geothermal areas in NW-Mexico, Las Tres Vírgenes (LTV) and Cerro Prieto (CP). The goal is to trace the origin of reservoir fluids and to place paleoclimate and structural-volcanic constraints in the region. Measured ³He/⁴He (R) ratios normalized to the atmospheric value (R_a = 1.386 × 10⁻⁶) vary between 2.73 and 4.77 and are compatible with mixing between a mantle component varying between 42 and 77% of mantle helium and a crustal, radiogenic He component with contributions varying between 23% and 58%. Apparent U–Th/⁴He ages for CP fluids (0.7–7 Ma) suggest the presence of a sustained ⁴He flux from a granitic basement or from mixing with connate brines, deposited during the Colorado River delta formation (1.5–3 Ma). Radiogenic in situ ⁴He production age modeling at LTV, combined with the presence of radiogenic carbon (1.89 ± 0.11 pmC – 35.61 ± 0.28 pmC) and the absence of tritium strongly suggest the Quaternary infiltration of meteoric water into the LTV geothermal reservoir, ranging between 4 and 31 ka BP. The present geochemical heterogeneity of LTV fluids can be reconstructed by mixing Late Pleistocene – Early Holocene meteoric water (58–75%) with a fossil seawater component (25–42%), as evidenced by Br/Cl and stable isotope trends. CP geothermal water is composed of infiltrated Colorado River water with a minor impact by halite dissolution, whereas a vapor-dominated sample is composed of Colorado River water and vapor from deeper levels. δD values for the LTV meteoric end-member, which are 20‰–44‰ depleted with respect to present-day precipitation, as well as calculated annual paleotemperatures 6.9–13.6 °C lower than present average temperatures in Baja California point to the presence of humid and cooler climatic conditions in the Baja California peninsula during the final stage of the Last Glacial Pluvial period. Quaternary recharge of the LTV geothermal reservoir is related to elevated precipitation rates during cooler-humid climate intervals in the Late Pleistocene and Early Holocene. The probable replacement of connate water or pore fluids by infiltrating surface water might have been triggered by enhanced fracture and fault permeability through contemporaneous tectonic–volcanic activity in the Las Tres Vírgenes region. Fast hydrothermal alteration processes caused a secondary, positive δ¹⁸O-shift from 4‰ to 6‰ for LTV and from 2‰ to 4‰ for CP geothermal fluids since the Late Glacial infiltration.     

Cloud radiative forcing in Asian monsoon region simulated by IPCC AR4 AMIP models

This study examines cloud radiative forcing (CRF) in the Asian monsoon region (0^o--50^oN,60^o--150^oE) simulated by Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) AMIP models. During boreal winter, no model realistically reproduces the larger long-wave cloud radiative forcing (LWCF) over the Tibet Plateau (TP) and only a couple of models reasonably capture the larger short-wave CRF (SWCF) to the east of the TP. During boreal summer, there are larger biases for central location and intensity of simulated CRF in active convective regions. The CRF biases are closely related to the rainfall biases in the models. Quantitative analysis further indicates that the correlation between simulated CRF and observations are not high, and that the biases and diversity in SWCF are larger than that in LWCF. The annual cycle of simulated CRF over East Asia (0^o--50^oN, 100^o--145^oE) is also examined. Though many models capture the basic annual cycle in tropics, strong LWCF and SWCF to the east of the TP beginning in early spring are underestimated by most models. As a whole, GFDL-CM2.1, MPI-ECHAM5, UKMO-HadGAM1, and MIROC3.2 (medres) perform well for CRF simulation in the Asian monsoon region, and the multi-model ensemble (MME) has improved results over the individual simulations. It is suggested that strengthening the physical parameterizations involved over the TP, and improving cumulus convection processes and model experiment design are crucial to CRF simulation in the Asian monsoon region.     

Impact of 4DVAR assimilation of rainfall data on the simulation of mesoscale precipitation systems in a mei-yu heavy rainfall event

The multi-scale weather systems associated with a mei-yu front and the corresponding heavy precipitation during a particular heavy rainfall event that occurred on 4 5 July 2003 in east China were successfully simulated through rainfall assimilation using the PSU/NCAR non-hydrostatic, mesoscale, numerical model （MM5） and its four-dimensional, variational, data assimilation （4DVAR） system. For this case, the improvement of the process via the 4DVAR rainfall assimilation into the simulation of mesoscale precipitation systems is investigated. With the rainfall assimilation, the convection is triggered at the right location and time, and the evolution and spatial distribution of the mesoscale convective systems （MCSs） are also more correctly simulated. Through the interactions between MCSs and the weather systems at different scales, including the low-level jet and mei-yu front, the simulation of the entire mei-yu weather system is significantly improved, both during the data assimilation window and the subsequent 12-h period. The results suggest that the rainfall assimilation first provides positive impact at the convective scale and the influences are then propagated upscale to the meso- and sub-synoptic scales.
Through a set of sensitive experiments designed to evaluate the impact of different initial variables on the simulation of mei-yu heavy rainfall, it was found that the moisture field and meridional wind had the strongest effect during the convection initialization stage, however, after the convection was fully triggered, all of the variables at the initial condition seemed to have comparable importance.     

Microbial Processes in Stratified Lake Doroninskoe(Transbaikal Region)

正In recent decades,meromictic ponds attract the attention of researchers in different directions,because here the character of the physical,chemical and biological processes differ from those of typical mixing waters(Kuznetsov,1970;Hutchinson,1969).In Transbaikalia widely distributed soda and salt lakes with different salinity.Notable among them is Lake Doroninskoye,which has a pronounced stratification for a     

江苏一次锢囚状MCS和相关中涡旋MCV的观测分析

利用常规地面和高空气象观测资料,结合气象卫星云图和雷达回波,分析了2009年6月14日15—23时(北京时,下同),造成江苏强对流天气的一个中尺度对流系统(MCS)的锢囚状特征的形成过程及其垂直结构。地面中尺度分析表明,雷暴高压东侧在飑前倒槽北端发展的闭合低压环流的东南气流将暖湿空气输送到冷性雷暴高压的北侧形成东南一西北向的暖舌,从而形成锢囚状的结构。长三角探空网资料的垂直结构分析表明,在对流层下部地面到850 hPa为冷性的雷暴高压,在对流层中部700 hPa为冷性的α中尺度涡旋(MCV),而500 hPa已转变为暖性的MCV。静力学关系可以说明MCV仅仅存在于700~500 hPa的原因和MCS下冷上暖的热力结构密切相关。