温度对橄榄蛏蚌耗氧和氨氮排泄的影响

The respiration metabolismand excretion of marinebivalves were studied by different researchers[1—6].Themetabolic rate of bivalves is influenced by a number ofvariables,includingtemperature,body size,oxygen ten-sion,food concentration,reproductive state,activityleveland physiological condition.The excreted metabolites ofbivalves include ammonia,urea,uric acid and others,with ammonia comprising70%of the total excretion.Solenaia oleivorais a proper freshwater bivalve in China.For the consumer it has the follo...     

香溪河水体中生源要素磷的时空分布研究

Phosphorus is an essential and oftenlimiting nutrientin both marine andfreshwater ecosystems,yetits oversup-plyis of concern in many environments due to its role ineutrophication[1].Phosphorus enters rivers from diffusecatchment sources(particularly agriculture)and point(effluent)sources.However,river systems have an im-portant internal capacity to remove or release phosphorusfrom/to the water column and to trans-form phosphorusbetween organic,inorganic,particulate and dissolvedforms.River bed…     

针刺法作用兔血管再狭窄模型的病理学研究

目的:探讨针刺作用动脉再狭窄的病理学改变,为针刺临床治疗冠状动脉成形术后再狭窄提供理论依据.方法:应用PTCA球囊导管对实验兔行双侧髂动脉内膜剥脱建立动脉粥样硬化模型术后,狭窄者再行PTCA球囊扩张术以建立再狭窄模型,动物组织进行HE染色,观察针刺后髂动脉,冠状动脉及主动脉内膜的形态学变化.结果:针刺组主动脉、髂动脉及冠状动脉脂斑面积与模型组差异不显(P＞0.05);内膜增生程度均较轻,内膜中VSMC、泡沫细胞较少;动脉内膜及中膜面积与模型组差异明显(P＜0.01).结论:针刺法对动脉血管再狭窄具有一定的防治作用.     

Effects of ELF magnetic fields on protein expression profile of human breast cancer cell MCF7

A case-control study in 1979 on electrical wiring configurations and childhood leukemia had stimulated interest in the issue that extremely low frequency magnetic fields (ELF MF) may have harmful biologi-cal effects especially on the incidence of human can-cer[1]. Since then, a large number of studies have been conducted to follow up this important result[2]. The majority of these studies indicate a weak association between exposure to 50―60 Hz ELF MF and the in-cidence of cancer; however…     

Silver stained polyacrylamide gels and fluorescence-based automated capillary electrophoresis for detection of amplified fragment length polymorphism patterns obtained from white-rot fungi in the genus Trametes

Silver stained denaturing polyacrylamide gels (PAGEs) and fluorescent denaturing automated capillary electrophoresis (CE) were used to detect amplified fragment length polymorphism (AFLP) patterns obtained from white-rot fungi belonging to the genus Trametes. AFLP fingerprinting detected by the fluorescence-based method as well as by silver staining showed a high discriminatory power in differentiating nine strains of Trametes ochracea, nine strains of Trametes hirsuta and ten isolates of Trametes versicolor. UPGMA dendrograms derived from fluorescently labelled and silver stained AFLP patterns were similar, but a few differences were detected especially in the clustering of T. ochracea and T. hirsuta strains. Compared to silver-stained AFLP, detection of fluorescent AFLP was fast, reliable and easy to perform and it facilitated surveying with a computerized analysis system. Fluorescent CE seems to be well suited for studying similarity between Trametes species.     

Response of a Pseudomonas aeruginosa biofilm community to DNA-damaging chemical agents

Pseudomonas aeruginosa strain RM4440 carries a plasmid-borne fusion of the P. aeruginosa recA gene promoter to a promoterless lux operon from Vibrio fisheri. We tested the response of RM4440 in a biofilm to exposure to a 1-h pulse of each of 17 chemicals known to be toxic to bacteria and other organisms. The induction of light produced from the recA-lux fusion present in RM4440 proved to be sensitive and specific for DNA-damaging chemicals when included in a biofilm environment. This study demonstrates the potential usefulness of this construct for in situ investigation of bacterial communities.     

Carbofuran degradation mediated by three related plasmid systems

Two carbofuran-metabolizing Sphingomonas strains, TA and CD, were isolated from soils with differing histories of exposure to carbofuran. These strains were compared with a previously described strain, Sphingomonas sp. CFO6, with regard to growth rate, formation of metabolites, and plasmid content and structure. Extensive regions of similarity were observed between the three different plasmid systems as evidenced by cross hybridization. In addition, all three systems harbor IS1412, an insertion sequence (IS) element involved in heat-induced loss of carbofuran phenotype in CFO6, and heat-induced carbofuran deficient mutants of all three strains correlated with loss of IS1412. A carbofuran deficient mutant of TA generated by induction of IS elements was complemented by reintroduction of the wild-type plasmid, confirming the presence of genes required for carbofuran metabolism on this plasmid. Carbofuran metabolism in these three strains is clearly linked via plasmids of different numbers and sizes that share extensive common regions, and carbofuran-degrading genes may be associated with active IS elements.