Potential effects of exploiting the Yunfu pyrite mine (southern China) on soil: evidence from analyzing trace elements in surface soil.

Trace element contamination caused by mining is a serious environmental problem. The potential effects of exploiting the Yunfu pyrite mine (southern China) on soil were investigated by determining trace elements in 56 surface soil samples from the vicinity of the Yunfu pyrite mine. The samples were acid dissolved and measured by an inductively coupled plasma mass spectrometry (ICP-MS). Principal component analysis and hierarchical cluster analysis were used to identify factors influencing the trace element contents and possible sources of the trace elements. The degree of trace element pollution was determined using the geological accumulation index Igeo. Monte Carlo simulations were used to assess the health risks posed. The results show that (1) six factors (parent material, mining activities, ore composition, rainfall, terrain, and other inputs) strongly affected the trace element contents of the soil samples. (2) There were three groups of trace elements, according to their possible sources. One group (Cs, Ga, Ge, Hf, Nb, Rb, Ta, Th, Ti, U, and Zr) mainly originated in parent rocks. Another group (Cr, Ni, Sr, and V) was mainly supplied by industrial plants and traffic emissions. The third group (Ba, Co, Cu, Mn, Pb, and Zn) was mainly supplied through pyrite ore exploitation processes. (3) Some samples were slightly to moderately polluted with Cs, Ga, Ge, Nb, Rb, Ta, and Ti. Most samples were moderately to highly polluted with Ba, Co, Cu, Mn, Pb, and Zn. (4) Trace elements in soil pose strong non-carcinogenic and carcinogenic health risks to people (particularly children) living near the Yunfu pyrite mine.

Biochemical and hemostatic mechanism of a novel thrombin-like enzyme.

Thrombin-like enzyme (TLE) plays a significant role in vessel injury hemostasis. A novel snake venom TLE (Agacutin) was purified from Agkistrodon Acutus snake venom. Structural analysis indicated that Agacutin is a heterodimer that has a MW of 29,402 Da, a pI value of 5.39, and optimum activity at 35 degrees C and pH 7.5. The N-terminal 15 amino acid sequences of Agacutin are DSSGWSSYEGHEYYV (small subunit) and DCSSGWSSYEEHQYY (large subunit). In vitro studies indicated that the coagulation activity of Agacutin was activated by Ca(+2) or inhibited by phenylmethanesulfonyl fluoride, but not influenced by heparin or hirudin. The arginine esterase activity and fibrinogen hydrolysis result showed that Agacutin only cleaves alpha-subunit and releases fibrinopeptide A. In vivo studies indicated that Agacutin iv (0.01-0.05 U/kg) shortened 30.2-49% of the rabbit blood clotting time, or ip (0.5-2.0 U/kg) shortened 29.7-73.1% of the mouse tail bleeding time. Agacutin does not influence APTT, platelet or euglobulin clotting time, and activate Factor II or XIII. It converts fibrinogen into the soluble fibrin that accelerates hemostasis at wound.

Piperidinium bis-(2-oxidobenzoato-κO,O)borate.

The asymmetric unit of the title compound, C(5)H(12)N(+)·C(14)H(8)BO(6) (-) or [C(5)H(12)N][BO(4)(C(7)H(4)O)(2)], contains two piperidinium cations and two bis-(salicylato)borate anions. The coordination geometries around the B atoms are distorted tetra-hedral. In the two mol-ecules, the aromatic rings are oriented at dihedral angles of 76.27 (3) and 83.86 (3)°. The rings containing B atoms have twist-boat conformations, while the two cations adopt chair conformations. In the crystal, the component species are linked by N-H⋯O hydrogen bonds. In the crystal structure, intra- and inter-molecular N-H⋯O hydrogen bonds link the mol-ecules.

[Identification of the related gene of mouse tolerant to exposure to perfluoroisobutylene by DDRT-PCR].

OBJECTIVE: The mice surviving acute exposure to low dose of perfluoroisobutylene (PFIB) could tolerant to lethal dose of PFIB. Discovering the gene related with the tolerance would be significant to find preventive agents for PFIB. METHODS: By static exposure to PFIB for 3 times, the survival animals could tolerate to lethal dose of PFIB. Three anchoring primers and 4 arbitrary primers were applied in differential display reverse transcription PCR (DDRT-PCR) of lung tissues and the products were analyzed by sequencing PAGE and silver staining. The differential DNA fragments were cloned and sequenced. RESULTS: There were obvious differences of gene expression between control and tolerant animals. Three expressed sequence tags (EST) have been cloned and sequenced,which were homologous to some mouse gene in Genbank. CONCLUSION: Specific gene up-regulation might be the cause of tolerance to PFIB, and they are very important to clarity the tolerant mechanisms to PFIB.

[Isolation, purification and identification of rat brain microvessels].

AIM: To isolate and purify the brain microvessels without intact neural cells used for cloning specific gene at the blood-brain-barrier. METHODS: Magnetic beads ranging from 200-500 nm were synthesized and infused into cerebral spheres through carotid arteries. The brain tissues were dissected by mechanic and enzymatic methods, and sieved to discharge tissues and large blood vessels. The brain microvessels labelled by magnetic beads were sorted in magnetic fields, and identified by morphology, molecular biology and biologic activity. RESULTS: Scanning electric micrograph of the obtained brain microvessels showed the vessels grossly free of adjoining neural cells except an occasional nerve ending. RT-PCR products of microtube-associated protein 2a, glutamine synthetase and CD31 from brain tissue had positive lanes, but only CD31 had positive lanes from isolated microvessels. The endothelial cells from isolated microvessels had more fluorescence than that from cultured endothelial cells. CONCLUSION: Highly purified microvessels without intact neural cells can be obtained by this method.