碱湖高产碱性蛋白酶菌的选育和产酶条件研究

以分离自碱湖的产碱性蛋白酶菌V．metschnikovii DL33为出发株,经紫外线、硫酸二乙酯多次复合诱变,获得一高产突变株V．Metschnikovii DL33—51,其产生的碱性蛋白酶活力是出发菌株的5．74倍,48h发酵液酶活由350U／mL提高至2010U／mL。同时对菌株DL33—51的产酶培养基和条件进行了优化,以最适产酶培养基26℃对V．metschnikovii DL33—51进行摇瓶发酵,发酵40h,酶活达3268U／mL。     

实验室海月水母大规模解体的初步研究

本实验针对两次突发的饲养海月水母(Aureliaaurita)大规模烂洞解体状况,通过对病灶处进行细菌培养,从其中每次发病水母中均各分离到2种优势病原菌菌株,利用PCR扩增和DNA测序技术,获得优势菌株16SrRNA基因序列,通过生物信息比对分析显示,导致两次海月水母发病的病原菌菌株分别为2种嗜冷杆菌(Psychrobacter sp.)和2种弧菌(Vibrio splendidusVibrio neptunius)。通过利用福林酚法进行此四种优势菌株的细菌发酵培养液蛋白酶活性的测定,结果显示,此4种细菌均具有较强的蛋白酶活性。根据实验结果推测,分离所得的2种嗜冷杆菌菌株(Paa1Paa2)和2种弧菌菌株(Vaa1Vaa2)作为此次发病海月水母的病原菌,有可能均是通过分泌胞外蛋白酶侵蚀水母伞体,从而导致伞体烂洞解体。通过本次实验分析,推测自然条件下水母暴发后的快速消亡是由水母自身免疫下降与细菌侵染的共同作用导致。     

基于BP神经网络的高频地波雷达海流空间插值

高频地波雷达是海洋环境监测的重要手段,当前已经实现对海流的业务化观测,但是外部因素常引起海流空间探测的不连续性。为解决此问题,尽量保障区域数据的完整性和准确性,本文将BP神经网络技术与空间插值相结合,建立了海流的BP神经网络插值模型,并进行了针对实测数据的缺失插值仿真,通过与反距离权重法和线性插值法插值结果的对比,分析该模型在区域海流大面积缺失、流速整体较大和流速整体较小3个方面的性能。结果表明,BP神经网络插值模型的海流预测效果明显优于其他两种方法,且在流场数据大范围缺失下也取得了良好的效果。     

Geological and Geochemical Characteristics of the Hydrothermal Clay Alteration in South Korea

Abstract: Hydrothermally altered areas forming pyrophyllite‐kaolin‐sericite‐alunite deposits are distributed in Chonnam and Kyongsang areas, Cretaceous volcanic field of the Yuchon Group. The Chonnam alteration area is located within depression zone which is composed of volcanic and granitic rocks of late Cretaceous age. The clay deposits of this area show the genetic relationship with silicic lava domes. The Kyongsang alteration area is mainly distributed within Kyongsang Basin comprising volcanic, sedimentary and granitic rocks of Cretaceous and Tertiary age. Most of the clay deposits of this area are closely related to cauldrons. Paleozoic clay deposit occurs in the contact zone between Precambrian Hongjesa granite gneiss and Paleozoic Jangsan quartzite of Choson Supergroup. Cretaceous igneous rocks of the both alteration areas belong to high K calc‐alkaline series formed in the volcanic arc of continental margin by subduction‐related magmatism. Chonnam igneous rocks show more enrichment of crustal components such as K, La, Ce, Sm, Nd and Ba, higher (La/Yb)cn ratio, and higher initial ⁸⁷Sr/⁸⁶Sr ratio (0. 708 to 0. 712) than those of Kyongsang igneous rocks. This might be due to the difference of degree of crustal contamination during Cretaceous magmatism. The most characteristic alteration minerals of Chonnam clay deposits are alunite, kaolin, quartz, pyrophyllite and diaspore which were formed by acidic solution. Those of Kyongsang clay deposits are sericite, quartz and pyrophyllite which were formed by weak acid and neutral solution. The formation ages of the clay deposits of two alteration areas range from 70. 1 to 81. 4 Ma and 39. 7 to 79. 4 Ma, respectively. The Daehyun clay deposit in Ponghwa area of Kyongsang province shows the alteration age range from 290 to 336 Ma. This result shows the different alteration episode from the hydrothermal alteration of Cretaceous to early Tertiary in the Kyongsang and Chonnam alteration areas. These data indicate, at least, three hydrothermal activities of Tertiary (middle to late Eocene), late Cretaceous (Santonian to Maastrichtian) and Paleozoic Carboniferous Periods in South Korea.     

Evolution of groundwater chemical composition under human activity in an oilfield

 Analysis and hydrogeochemical modeling of hydrocarbonate groundwater, including its buffering geochemical properties, have demonstrated that this water has undergone a geochemical transformation almost throughout the whole of one industrial region. It is known that hydrocarbonate groundwater possesses a high protective natural geochemical potential, supporting neutralization of acid atmospheric precipitation. Natural hydrocarbonate water undergoes three stages of anthropogenic transformation caused by acid atmospheric precipitation over more than 50 years. The first stage is transformation of neutral hydrocarbonate water into alkaline water, accompanied by calcite precipitation and sodium carbonate dissolution from the unsaturated zone. The second stage is transformation of alkaline water into neutral hydrocarbonate water; the hydrocarbonate content, being less than the lower limit for background concentrations, showed reduced water buffering properties or protective potential relative to acid precipitation. The third stage is transformation of neutral hydrocarbonate water into acidic water, with a complete loss of protective geochemical potential. This unfavorable ecological situation with natural geochemically hydrocarbonate groundwater shows that natural groundwater less protected from the impact of acid atmospheric precipitation is in a worse ecological condition, which is confirmed by observations in northern and Western Europe and other regions of the world. Received: 30 October 1997 · Accepted: 23 March 1998     

环境因子对鳗弧菌生长和胞外蛋白酶表达的影响

鳗弧菌(Vibrio anguillarum)是一种水产动物的重要致病菌,鳗弧菌分泌的胞外蛋白酶是该菌的致病因子之一.研究了环境因子对鳗弧菌W-1生长及胞外蛋白酶表达的影响.结果表明,鳗弧菌的最适生长温度为28℃,菌体生长量在21 h达到最高,胞外蛋白酶的活力在24 h最高.在37℃培养时,菌体生长和酶活力显著降低;添加葡萄糖、蔗糖、麦芽糖等碳源物质均能显著促进菌体的生长,但对于胞外蛋白酶表达有明显抑制作用;1 mmol/L EGTA对茵体的生长和胞外蛋白酶表达没有明显影响,而1 mmol/L的EDTA强烈抑制鳗弧菌的生长及其胞外蛋白酶的表达.添加不同浓度的氨苄青霉素对菌体的生长及其胞外蛋白酶表达有明显的抑制作用.     

Long chain alkyl heteroaromatics in coal identified by tandem mass spectrometry

The presence of a series of long chain alkyl aromatic and heteroaromatic hydrocarbons was confirmed in a Utah boghead coal using tandem mass spectrometry. Parent and neutral loss scans were utilized to characterize the complex mixture and daughter scans were used to identify individual components.     

Neutral Leaching of Low-Grade Pyrolusite with High Silica Content

Leaching studies of low-grade pyrolusite, containing 11.84% Mn with high silicon, were carried out using sodium sulfite as a reductant in ammonium sulfate medium. Various process parameters including temperature, leaching time, solid-liquid ratio, quantity of ammonium sulfate, as well as the amount of reducing agent were studied in detail. The manganese extraction yield was the response of the process. Temperature and reagent concentration exerted the most important positive effect on the manganese extraction. The optimized conditions showed that when the amount of reducing agent was a stoichonmetric amount, over 90% manganese extraction and the lowest impurities were achieved, the amount of heavy metal impurities in the manganese leaching liquid was less than 5 mg/L, and almost no iron and aluminum were extracted in 3 mol/L ammonium sulfate concentration at 100 ℃ in 45 min.     

利用GPS掩星资料反演地球中性大气参数折射角方法研究

对利用GPS掩星资料反演地球中性大气参数的原理作了简要介绍，在此基础上对消除电离层影响的改正方法、Abel反演积分上限的确定、上边界测量折射角的优化方法进行了探讨。针对UCAR的Level2数据，在数据预处理工作的基础上，利用特定掩星事件的数据进行了反演计算，并对计算结果进行了分析。     

GPS测量的中性大气折射改正的研究

中性大气对ＧＰＳ信号的折射影响是ＧＰＳ测量的重要误差源之一。测量定位的垂直分量精度的提高,受到中性大气延迟改正程度很强制约。