Effects of Bioavailable Heavy Metal Species,Arsenic, and Acid Drainage from Mine Tailings on a Microbial Community Sampled Along a Pollution Gradient in a Freshwater Ecosystem

Sediment and water samples representing a pollution gradient in a long, narrow lake polluted at one end by heavy metals, arsenic, and acid drainage from mine tailings, together with samples from an unpolluted reference lake, were analyzed to determine effects of pollutants on the microbial community of the polluted lake. Ribosomal ribonucleic acid, fatty acid, and phospholipid analyses, along with assays of CO₂ production, denitrification, and enzyme activities, were performed to characterize the microflora; and environmental conditions were defined by various physicochemical analyses, including determination of bioavailable metal species. Mine waste pollution fostered the growth of Holophagal Acidobacteria, green sulphur bacteria, and α-Proteobacteria but inhibited numerous other types of microorganisms, reducing the overall productivity, biomass, and biodiversity of the microflora. The beneficial effects imply toleration of pollutants, suppression of competing or antagonistic species, and utilization of biogenic sulphide; and the toxic effects are attributable to bioavailable metals, arsenic, and sulphuric acid produced by oxidation of sulphides. The bioavailability and toxicity of sediment-bound metals were evidently increased by acidification, elevation of sediment Eh, and inhibition of metal-immobilizing bacteria by pollutants but were decreased by metal-scavenging oxyhydroxides, sulphide, and organic matter. Metal toxicity also depended on specific metal properties (e.g., electronegativity), providing a basis for inferring mechanisms of toxicity and oxidation states of metals and explaining differences in relative toxicity. The pollutants harmed the ecosystem as a whole by inhibiting microorganisms that performed crucial ecological functions, notably oxygen-releasing photosynthesis, decomposition and humification of organic matter, nutrient recycling, and control of metal availability.     

New Insights into the Developing Rabbit Brain Using Diffusion Tensor Tractography and Generalized q-Sampling MRI

The use of modern neuroimaging methods to characterize the complex anatomy of brain development at different stages reveals an enormous wealth of information in understanding this highly ordered process and provides clues to detect neurological and neurobehavioral disorders that have their origin in early structural and functional cerebral maturation. Non-invasive diffusion tensor magnetic resonance imaging (DTI) is able to distinguish cerebral microscopic structures, especially in the white matter regions. However, DTI is unable to resolve the complicated neural structure, i.e., the fiber crossing that is frequently observed during the maturation process. To overcome this limitation, several methods have been proposed. One such method, generalized q-sampling imaging (GQI), can be applied to a variety of datasets, including the single shell, multi-shell or grid sampling schemes that are believed to be able to resolve the complicated crossing fibers. Rabbits have been widely used for neurodevelopment research because they exhibit human-like timing of perinatal brain white matter maturation. Here, we present a longitudinal study using both DTI and GQI to demonstrate the changes in cerebral maturation of in vivo developing rabbit brains over a period of 40 weeks. Fractional anisotropy (FA) of DTI and generalized fractional anisotropy (GFA) of GQI indices demonstrated that the white matter anisotropy increased with age, with GFA exhibiting an increase in the hippocampus as well. Normalized quantitative anisotropy (NQA) of GQI also revealed an increase in the hippocampus, allowing us to observe the changes in gray matter as well. Regional and whole brain DTI tractography also demonstrated refinement in fiber pathway architecture with maturation. We concluded that DTI and GQI results were able to characterize the white matter anisotropy changes, whereas GQI provided further information about the gray matter hippocampus area. This developing rabbit brain DTI and GQI database could also be used for educational purposes and neuroscience investigations.     

Cardiac myosin binding protein C and MAP-kinase activating death domain-containing gene polymorphisms and diastolic heart failure

Objective

Myosin binding protein C (MYBPC3) plays a role in ventricular relaxation. The aim of the study was to investigate the association between cardiac myosin binding protein C (MYBPC3) gene polymorphisms and diastolic heart failure (DHF) in a human case-control study.

Methods

A total of 352 participants of 1752 consecutive patients from the National Taiwan University Hospital and its affiliated hospital were enrolled. 176 patients diagnosed with DHF confirmed by echocardiography were recruited. Controls were matched 1-to-1 by age, sex, hypertension, diabetes, renal function and medication use. We genotyped 12 single nucleotide polymorphisms (SNPs) according to HapMap Han Chinese Beijing databank across a 40 kb genetic region containing the MYBPC3 gene and the neighboring DNA sequences to capture 100% of haplotype variance in all SNPs with minor allele frequencies ≧5%. We also analyzed associations of these tagging SNPs and haplotypes with DHF and linkage disequilibrium (LD) structure of the MYBPC3 gene.

Results

In a single locus analysis, SNP rs2290149 was associated with DHF (allele-specific p = 0.004; permuted p = 0.031). The SNP with a minor allele frequency of 9.4%, had an odds ratio 2.14 (95% CI 1.25–3.66; p = 0.004) for the additive model and 2.06 for the autosomal dominant model (GG+GA : AA, 95% CI 1.17–3.63; p = 0.013), corresponding to a population attributable risk fraction of 12.02%. The haplotypes in a LD block of rs2290149 (C-C-G-C) was also significantly associated with DHF (odds ratio 2.10 (1.53–2.89); permuted p = 0.029).

Conclusions

We identified a SNP (rs2290149) among the tagging SNP set that was significantly associated with early DHF in a Chinese population.     

Influence of protein histidine phosphatase overexpression and down-regulation on human umbilical-vein endothelial cell viability

PHP (protein histidine phosphatase) is expressed by mammalian tissues, particularly in blood vessel walls. We investigated whether PHP plays a significant role in endothelial cells. By Western blot and immunofluorescence analysis PHP was found in HUVEC (human umbilical-vein endothelial cells). Overexpression of PHP by the use of a plasmid vector, pIRES2-AcGFP1-PHP, induced apoptosis in HUVEC. To exclude the possibility that increased cellular protein alone unspecifically caused cell damage, the inactive H53A mutant of PHP was also overexpressed as a control; it did not lead to apoptosis. Down-regulation of PHP by the RNAi (RNA interference) technique did not affect cell viability. In conclusion, HUVEC are damaged by overexpression, but not down-regulation, of PHP, suggesting a pronounced impact of the enzyme on the cells when its activity is increased.     

Characterization of the genes coding for the high molecular weight glutenin subunits in Lophopyrum elongatum

In order to reveal the evolution of Glu-E1 loci of Lophopyrum elongatum (Host) A. L?ve and find novel alleles for wheat quality breeding, four Glu-1 alleles were isolated and characterized via genomic PCR, from this wheat-related species. Of them, 1Ex2 and 1Ey2 were novel alleles, which differ from all the previously known HMW-GS alleles of L. elongatum. Two alleles 1Ex1 and 1Ey2, which contain intact open reading frames, have been successfully expressed in E. coli. The expressed proteins showed similar electrophoresis mobility with the candidate high molecular weight glutenin subunit bands found in seeds. Sequence alignment indicated that proteins encoded by the novel alleles showed similar primary structure with those of wheat and other wheat-related grasses, however, they possess some unique modifications in their own structure. For example, the number of residues in the N-terminal domain is different from those of wheat, an irregular tripeptide present between two nonapeptide motifs and a unique cysteine position in the repetitive region. Phylogenetic analyses using N-terminal conserved sequences showed that 1Ex2 was homologous to those from the D genome; but 1Ey2 was homologous to a y-type allele 1Ky from the K genome. The evolution relationship of Glu-E1 alleles and the possible utilization of the alleles in wheat breeding are discussed.     

Application of solvent engineering to optimize lipase-catalyzed 1,3-diglyacylcerols by mixture response surface methodology

1,3-Diacylglycerol has been introduced in Japan as a cooking oil under the trade name of Econa to reduce body fat accumulation. Solvent engineering was applied to determine the optimum solvent mixtures for the lipase-catalyzed synthesis of 1,3-DAG by mixture response surface methodology. n-Hexane was required to maintain the lipase activity and the product selectivity could be adjusted by changing the hydrophobicity of reaction medium. The optimum yield (40%) of 1,3-DAG synthesis was obtained with n-hexane/octane (1:1, v/v).     

A modified technique for tail cuff pressure measurement in unrestrained conscious rats

In physiological experiments, it is essential to measure arterial pressure (AP) and heart rate (HR) in animals. Tail cuff pressure (TCP) measurement using photoelectric volume oscillometry has been commonly used. We designed a new technique for continuous measurement of AP and HR in conscious, unrestrained rats. This is based on the observation that fixation of the rat's tail with tape keeps the animal in position without struggling. The animal is free to move its body. To test the accuracy of this new technique, Sprague-Dawley rats underwent four AP and HR measurement techniques. These included a new unrestrained method (UR), which was compared to the following three methods: traditional restrained TCP method with restrainer, direct monitoring of AP and HR with femoral artery catheterization and a combination of photoelectric volume oscillometry (with body heating to 37 degrees C) and femoral arterial recording. The results show that the modified UR measurement provides accurate data on AP and HR. This method obtains a lower value of HR and similar mean AP when compared to direct monitoring from femoral arterial catheterization. Accordingly, the modified unrestrained TCP measurement can be used in conscious rats as a noninvasive method.     

甘蓝型油菜理化诱变和突变体库的构建

利用射线与甲基磺酸乙酯（EMS）溶液诱变技术复合处理甘蓝型油菜高油605的成熟种子。经田间M2筛选和M3验证, 共筛选到152个叶色、叶形、株高、分枝数、分枝角度、茎径、茎色、花色、花瓣数、花瓣大小、花蕊形态、雄性不育、死蕾及开花期等性状发生变异的突变体, 占M2诱变群体总数的12.67%。利用水培法进行M3和M4株系的子叶和根系变异性状筛选和验证, 发现子叶和根系变异频率分别为12.78%和7.07%。现已构建了包括叶片、株型、花器、子叶、根系及部分生理性状变异类型的突变体库, 可为今后油菜遗传改良和功能基因组学研究提供更多的种质资源。     

超广谱β-内酰胺酶肺炎克雷伯菌噬菌体F20的分离鉴定及其对小鼠败血症治疗效果

【背景】肺炎克雷伯菌是引起临床感染的重要条件致病菌之一,肺炎克雷伯菌中产超广谱β-内酰胺酶(Extended-spectrum beta-lactamases,ESBLs)的耐药菌株增多迫切需要找到一种新的治疗方法。【目的】自污水中分离超广谱β-内酰胺酶肺炎克雷伯菌噬菌体,并明确其生物学特性、观察其治疗小鼠产ESBLs肺炎克雷伯菌感染的疗效。【方法】电镜观察F20形态,调查其噬菌谱、生长曲线等生物学特性。建立小鼠败血症感染模型观察F20治疗小鼠肺炎克雷伯菌感染的疗效。【结果】F20在其宿主菌的菌苔上形成裂解性噬菌体所具有的完全透明的噬菌斑,电镜观察F20具典型的有尾噬菌体目长尾病毒科病毒的形态特征。一步生长曲线显示F20的潜伏期为18 min,裂解量为89 PFU/细胞。稳定性试验显示F20在pH 5.0-9.0及50°C环境均具良好稳定性。使用噬菌体F20对败血症小鼠治疗后,治疗组小鼠各外周血和各脏器(肺脏、肝脏、脾脏和肾脏)中的细菌数也显著小于对照组细菌数(P0.001),与对照组相比下降大约1–3数量级。F20治疗败血症小鼠存活率达到87.5%,无毒副作用,而对照组小鼠在1 d内全部死亡,可显著提高小鼠的存活率(P0.001)。【结论】新分离的裂解性噬菌体F20在小鼠体内能安全有效地治疗超广谱β-内酰胺酶肺炎克雷伯菌引起的败血症,可作为生物抗菌剂的有效成分。