细菌碳酸酐酶促进形成的碳酸盐矿物

微生物促进碳酸盐矿化机理的研究对于全球碳循环和土壤的形成与演化等科学问题具有重要的意义。为了探究细菌胞外碳酸酐酶（CA）在碳酸盐矿化过程中所起的作用,本文采用硫酸铵析出蛋白质和Tris-H2SO4缓冲液溶解蛋白质的方法提取MF-2菌株分泌的胞外CA,将其添加于一水乙酸钙—胰蛋白胨（不含碳酸根）体系中并进行了120 h的化学实验。同时设置一组不含CA的对照实验。实验结束后用离心法将固相和液相分离。利用X-射线衍射仪（XRD）和扫描电子显微镜（SEM/EDS）对沉淀物的矿物成分、元素组成和形态进行了研究,利用电感耦合等离子体发射光谱仪（ICP-OES）测定了溶液中的Ca2+浓度。实验结果表明:（1）在节杆菌属MF-2菌株胞外CA作用下形成了肉眼可见的沉淀物,其重量随着反应时间的延长而逐渐增大,而溶液中钙离子浓度随着反应时间的延长而逐渐降低。用双氧水（30%）处理的结果显示,碳酸盐矿物是沉淀物的主要组分。对照实验形成的沉淀物明显少于CA实验,而且其主要由有机物质组成。这充分地说明,MF-2菌株胞外CA可以显著地促进碳酸盐矿物沉淀。（2）在有胞外CA参与的实验早期（第48 h之前）,未形成任何结晶态物质;在实验的中后期,形成的矿物以方解石为主,含少量或不含球霰石。这明显不同于MF-2菌株的培养实验。在后一种情况下仅形成球霰石一种矿物。（3）胞外CA作用下形成的矿物形态包括菱面体形、球形和半球形,其中菱面体形矿物占主导地位。这也有别于MF-2菌株的培养实验（以球状和碗状为主）。对多张SEM照片进行的统计结果显示,菱面体形矿物所占比例有随着反应时间的延长而逐渐降低的趋势（即球形和半球形所占比例逐渐升高）,从第48 h的接近100%降低至第120 h的84%。（4）MF-2菌株胞外CA促进碳酸钙沉淀的主要机制是其加速CO2的水化反应,参与反应的CO2可能主要源于空气。      

A new species of the genus Besania Brough 1939 from the Middle Triassic of Canton Grisons (Switzerland) with a discussion of the phylogenetic status of the taxon

Recent excavations in the Middle Triassic Prosanto Formation (Ladinian, Ct. Grisons, Switzerland) have produced new material of the genus Besania Brough 1939. These specimens show many previously unrecorded details. Some features differ from those of the type species Besania micrognathus, and we therefore erect a new species, Besania schaufelbergeri sp. nov. This new material has prompted a re-evaluation of the phylogenetic interrelationships of the genus. The taxon seems to be closely related to basal Halecostomi. An erratum to this article is available at .     

甲醛溶液对发头裸腹溞及其体表聚缩虫影响的试验

不同浓度的甲醛溶液对枝角类发头裸腹溞Moinairrasa的致毒效应以及对其体表附着的聚缩虫Zoothamniumsp．的杀灭效果的试验结果表明，12h、24h两个作用时段中，甲醛浓度与发头探腹溞相对存活率之间以及甲醇浓度与发头裸腹溞表聚缩虫营养体脱落率之间存在一定的函数关系．在确立上述函数基础上，可得出控制聚缩虫感染的两种有效方法：①在保证溞存活率不低于66％的情况下，选用最低有效浓度（19．mg／kg）的甲醛溶液作用24h可杀灭100％聚缩虫；②在保持溞存活率较高（70％－90％）的情况下，选用相应浓度的甲醛液作用24h杀灭87％－29％聚缩虫，并辅以更换新水等措施，也可将聚缩虫感染的危害控制在一定的范围内．     

藏北申扎、班戈地区奥陶纪和志留纪的一些头足类化石

文内描述的头足类化石采自藏北申扎县柯耳多组和班戈县东卡组,这些头足类化石分别属于塔飞角石目薇角石科、珠角石目链角石科以及肿角石目约维兰角石科。其中约维兰角石科分子系首次在藏北发现。笔者认为柯耳多组的时代属于中奥陶世,东卡组的时代当属于早至中志留世。 由于中奥陶世Sinoceras以及早至中志留世约维兰角石科分子在藏北的发现,表明西藏海域与华中—西南区浅海从中奥陶世到中志留世时都是相通连的。     

边眼虫属在新疆西准噶尔地区的发现

在新疆西准噶尔地区塔尔巴哈台山首次发现边眼虫属的一个新种,定名为Plagiolariaeminensis Guo (Sp.nov.).化石产于中泥盆统库鲁木迪组下部.     

Isolation and characterization of phenanthrene-degrading strain Sphingomonas sp. GY2B

Polycyclic aromatic hydrocarbons （PAHs） are of great concern since most of them have been shown to be toxic, mutagenic, and carcinogenic. Bioremediation, based on certain species of microorganisms, is regarded as an alternative method to detoxify or remove PAHs from the contaminated sites. Phenanthrene has been often used as a model substance for microbial metabolism of ＂bay-region＂ and ＂K-region＂ containing carcinogenic PAH. The focus of the present study is to isolate and identify microorganisms which could use phenanthrene as the sole carbon and energy source. Such microorganisms are expected to be of interest as a source organism for the bioremediation of PAHs polluted soils. The bacterial consortia were enriched from PAH contaminated soils with water-silicon oil biphasic systems. An aerobic bacterial strain efficiently utilizing phenanthrene as the sole carbon and energy source was isolated from bacterial consortia GY2 and identified as Sphingomonas sp. strain GY2B. Strain GY2B was susceptible to some common used antibiotics such as cefuroxime, chloramphenicol, erythromycin and tetracycline and intermediate susceptible to amoxycillin. Moreover, no plasmids could be isolated from strain GY2B using the standard alkaline-SDS method. At pH 7.4 and 30℃ strain GY2B had an optimal growth condition and in this condition above 99.8% phenanthrene was degraded under initial concentration of 100 mg/L. The addition of low concentration of glucose （10-200 mg/L） in MSM containing 100 mg/L phenanthrene could enhance the growth of strain GY2B, while the high concentration of glucose （〉500 mg/L） could exert an inhibitive effect on cell growth. Besides phenanthrene, strain GY2B could also use naphthalene, phenol, 1-hydroxy-2-naphthoic acid, 2-naphthol, salicylic acid and catechol as the sole carbon and energy source. The growth of strain GY2B on salicylic acid and catechol showed that the degradation of phenanthrene might follow salicylate pathway.     

Predation of the beetle Rhantus sikkimensis (Coleoptera: Dytiscidae) on the larvae of Chironomus Meigen (Diptera: Chironomidae) of the Darjeeling Himalayas of India

The dytiscid beetle Rhantus sikkimensis, Regimbart, 1899 (Coleoptera: Dytiscidae), a member of the freshwater insect communities of the Darjeeling Himalayas, were noted to predate on the coexisting larvae of Chironomus sp. Meigen. Evaluation of predation by R. sikkimensis on Chironomus sp. larvae, in the laboratory, revealed that a single adult morph of R. sikkimensis could kill and consume on an average 10–90 and 10–78 numbers of small and large Chironomus sp. larvae, respectively, per day, depending on the prey density. The attack rate ranged between 520 and 537, and the handling time ranged between 4.3 and 8.6 depending on the size of the preys. The predation varied with respect to predator density also, with a maximum of 151 larvae killed by three predators per day. Two indices of predation, ingestion rate (IR) ranging between 13.33 and 74.15 larvae/day/predator and clearance rate (CR) ranging between 19.67 and 39.99 L prey/day/predator, varied with the prey size and predator density, significantly, when the predation was observed for 9 consecutive days, at two predator densities. It was also noted that R. sikkimensis predated on an average 9.8 larvae of Chironomus sp. and 1 larva of Culex sp., when the larvae of both the species are present together as preys, showing a preference for the Chironomus sp. larvae.     

Fossil findings from the Sıcak Çermik fissure ridge-type travertines and possible hominid tracks,Sivas, Central Turkey

S?cak Çermik (Sivas) is an important geothermal and recent travertine formation area in Central Anatolia. The majority of travertines found in the region comprise fissure-ridge type travertines according to morphological classification. At the location called Tepe Çermik within the travertine area, fill containing fossil bone fragments of Equus sp., Bovidae and other abundant animals formed within the fracture axis of a N–S striking fissure-ridge travertine developed under control of tectonic forces. The finds of these fossils in fissure-ridge travertines linked to tectonic forces indicates formation of a unique fossil environment created under the control of these forces. The Accelerator Mass Spectrometry Radiocarbon Dating analyses of fossils from the study area determined the fills were older than 43,000 years. The U/Th age of a sample from the most recently-formed banded travertine in the axis of the fracture was identified as 278,540 ± 18,436 years. As a result, the ages of fossils found within this fill are thought to be between 43,000 and 278,540 ± 18,436 years old. The high amount of perissodactyla and artiodactyla fossils found within fill in the axis of the fissure-ridge travertine probably indicates the presence of hominids who chose the region for hunting or settlement. The Equus sp. and Bovidae fossil samples found in the axis of the fracture indicate that in the dry and cold glacial period the paleogeography in a large portion of Anatolia comprised desert-like steppe.     

颤藻对6种抗生素敏感性的研究

蓝藻是一种原核藻类,其结构和遗传复杂性同革兰氏阴性菌相似,具有独立的遗传结构—质粒和天然的转化和重组系统,所以蓝藻不仅是植物光合作用、叶绿体起源和植物进化研究的理想材料,还可能成为高等植物基因表达的重要宿主[1]。