连续施用无害化污泥堆肥对沙质潮土活性有机氮组分的影响

以河南省沙质潮土为研究对象,通过2012-2016年田间连续定位试验,在小麦-玉米轮作制度下,研究单施化肥(CK)、添加污泥堆肥(CS)15 t·hm^-2(CS₁)、30 t·hm^-2(CS₂)和45 t·hm^-2(CS₃)对土壤活性氮各组分及其分配比例的影响.结果表明: 连续施用污泥堆肥能够显著提高土壤含水率,降低土壤pH,提高土壤有机碳、全氮和速效养分含量,其中全氮(TN)含量显著增加了93.1%～284.3%;施用污泥堆肥45 t·hm^-2显著提高了土壤轻组有机氮(LFON)、颗粒有机氮(PON)和微生物生物量氮(MBN).污泥堆肥促进了颗粒态有机氮(PON/TN)和微生物生物量氮(MBN/TN)分配,在CS₂处理下分别显著提高了12.3%和539.9%,而降低了土壤轻组有机氮(LFON/TN)和溶解性有机氮(DON/TN)分配,分别降低了17.3%～40.1%和38.5%～71.3%.总体上,活性氮组分对TN的贡献为:PON>LFON>DON>MBN.主成分分析表明,CS₂和CS₃处理下活性氮含量及其分配比例载荷值较高;冗余分析表明,土壤理化指标(pH除外)和生物学指标与活性氮含量及其分配比例呈正相关.污泥堆肥可提供大量稳定性有机物质,影响土壤物理、化学和生物学特性,促进土壤氮素向活性氮的形式转化,当污泥堆肥施用量达30、45 t·hm^-2时培肥效果显著,可用作沙质潮土的改良材料.     

Impact of reduced vancomycin susceptibility on the therapeutic outcome of MRSA bloodstream infections

Background

Resistance to anti-tuberculosis drugs is a serious public health problem. Multi-drug resistant tuberculosis (MDR-TB), defined as resistance to at least rifampicin and isoniazid, has been reported in all regions of the world. Current phenotypic methods of assessing drug susceptibility of M. tuberculosis are slow. Rapid molecular methods to detect resistance to rifampicin have been developed but they are not affordable in some high prevalence countries such as those in sub Saharan Africa. A simple multi-well plate assay using mycobacteriophage D29 has been developed to test M. tuberculosis isolates for resistance to rifampicin. The purpose of this study was to investigate the performance of this technology in Kampala, Uganda.

Methods

In a blinded study 149 M. tuberculosis isolates were tested for resistance to rifampicin by the phage assay and results compared to those from routine phenotypic testing in BACTEC 460. Three concentrations of drug were used 2, 4 and 10 μg/ml. Isolates found resistant by either assay were subjected to sequence analysis of a 81 bp fragment of the rpoB gene to identify mutations predictive of resistance. Four isolates with discrepant phage and BACTEC results were tested in a second phenotypic assay to determine minimal inhibitory concentrations.

Results

Initial analysis suggested a sensitivity and specificity of 100% and 96.5% respectively for the phage assay used at 4 and 10 μg/ml when compared to the BACTEC 460. However, further analysis revealed 4 false negative results from the BACTEC 460 and the phage assay proved the more sensitive and specific of the two tests. Of the 39 isolates found resistant by the phage assay 38 (97.4%) were found to have mutations predictive of resistance in the 81 bp region of the rpoB gene. When used at 2 μg/ml false resistant results were observed from the phage assay. The cost of reagents for testing each isolate was estimated to be 1.3US$ when testing a batch of 20 isolates on a single 96 well plate. Results were obtained in 48 hours.

Conclusion

The phage assay can be used for screening of isolates for resistance to rifampicin, with high sensitivity and specificity in Uganda. The test may be useful in poorly resourced laboratories as a rapid screen to differentiate between rifampicin susceptible and potential MDR-TB cases.     

腺病毒介导的Wnt10b对HaCaT细胞迁移的作用及机制

目的:探讨Wnt10b对Ha Ca T表皮细胞迁移的影响及机制。方法:分别用重组腺病毒Ad-GFP、Ad-GFP-Wnt10b感染Ha Ca T表皮细胞,利用细胞免疫荧光技术检测腺病毒Ad-GFP-Wnt10b感染细胞后的过表达情况;采用细胞划痕实验,于不同时间点观察并记录经Wnt10b处理后,Ha Ca T细胞体外迁移功能的改变;进一步采用Westen blot技术检测不同腺病毒处理后,Ha Ca T细胞中Wnt信号关键分子β-catenin、细胞粘附分子E-cadherin表达的改变情况。结果:1Ad-GFP-Wnt10b感染Ha Ca T细胞48 h后,细胞内GFP表达上调,细胞免疫荧光染色显示Wnt10b处理组高表达Wnt10b蛋白;2Ha Ca T细胞经Ad-GFP-Wnt10b处理后,细胞创面愈合速度明显增快;3Wnt10b处理组细胞β-catenin蛋白表达水平显著高于对照组,而E-cadherin蛋白表达水平显著低于对照组。结论:Wnt10b能促进Ha Ca T细胞迁移,且该效应涉及经典Wnt/β-catenin信号的激活及由E-cadherin介导的细胞粘附性的减弱。     

甜瓜乙烯应答因子基因在果实发育成熟过程中的表达特性

根据已报道的甜瓜CMe-ERF1和CMe-ERF2基因cDNA序列设计合成特异性引物,应用RT-PCR技术从甜瓜品种‘河套蜜瓜’成熟果实中克隆得到CMe-ERF1和CMe-ERF2基因cDNA全长编码区序列,分别为498bp和822bp.序列比对分析表明,得到的cDNA序列与已报道的Andes甜瓜相应基因的cDNA序列完全一致.果实不同发育时期实时定量PCR检测结果表明,CMe-ERF1、CMe-ERF2基因表达与甜瓜果实成熟及乙烯生成量显著相关,表明该基因可能对果实成熟起重要作用.     

A galaxy of folds

Many protein classification systems capture homologous relationships by grouping domains into families and superfamilies on the basis of sequence similarity. Superfamilies with similar 3D structures are further grouped into folds. In the absence of discernable sequence similarity, these structural similarities were long thought to have originated independently, by convergent evolution. However, the growth of databases and advances in sequence comparison methods have led to the discovery of many distant evolutionary relationships that transcend the boundaries of superfamilies and folds. To investigate the contributions of convergent versus divergent evolution in the origin of protein folds, we clustered representative domains of known structure by their sequence similarity, treating them as point masses in a virtual 2D space which attract or repel each other depending on their pairwise sequence similarities. As expected, families in the same superfamily form tight clusters. But often, superfamilies of the same fold are linked with each other, suggesting that the entire fold evolved from an ancient prototype. Strikingly, some links connect superfamilies with different folds. They arise from modular peptide fragments of between 20 and 40 residues that co‐occur in the connected folds in disparate structural contexts. These may be descendants of an ancestral pool of peptide modules that evolved as cofactors in the RNA world and from which the first folded proteins arose by amplification and recombination. Our galaxy of folds summarizes, in a single image, most known and many yet undescribed homologous relationships between protein superfamilies, providing new insights into the evolution of protein domains.     

无菌豚鼠与普通豚鼠血液学参数的比较

目的对普通级豚鼠进行剖宫产,培育无菌豚鼠模型,并比较无菌豚鼠和普通级豚鼠的血液学参数。方法行子宫摘除术摘除子宫,在无菌隔离器中将子宫剥离取仔,用人工哺乳的方法将仔豚鼠培育成无菌豚鼠,并在固定的周期检测豚鼠的无菌情况。采用全血细胞计数分析仪、全自动血液生化分析仪测定无菌豚鼠、普通豚鼠的血常规和血生化参数。用SPSS12.0进行统计分析。结果无菌豚鼠和普通豚鼠在白细胞(WBC)、嗜碱性粒细胞数(BA#)、单核细胞百分比(MO)、血红蛋白浓度(MCHC)、中性粒细胞数(NE#)、嗜酸性粒细胞数(EO#)、淋巴细胞数(LY#)七个血常规指标上有差异显著性,其他指标没有显著性差异;谷丙转氨酶(ALT)、乳酸脱氢酶(LDH)、总蛋白(TP)、白蛋白(ALB)、葡萄糖(GLU)、总胆固醇(CHO)、总胆红素(TBIL)、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)、甘油三酯(TG)、球蛋白(GLO)、A/G、K、Na、谷酰转肽酶(GGT)15个指标上差异有显著性,其他指标差异无显著性。结论通过规范的子宫摘除术和人工喂养的方法获得符合标准的无菌豚鼠,与普通豚鼠在多项血液学指标上差异有显著性。     

BN P 的测定和临床应用的研究进展

B型利钠肽是一种具有利尿作用的内源性肽,其对早期发现心衰病人、心衰病人的分级、区分心衰及其他原因引起的呼吸困难、监测心衰治疗、提示心衰病人预后、识别有无左室功能不全及急性冠脉综合症的风险评估方面具有重要临床应用价值。本文主要介绍了B型利钠肽的测定及临床应用。     

On the Application of Computer Graphics Technique to Reconstruct Three-Dimension of Coal Ball Plants

This paper reports a new way by which three-dimensional images of coal ball plants are revealed conveniently. In order to reconstruct outer images of coal ball plants, especially seeds, three different reconstruction methods (additional method, symmetric method and mixed method) have been developed. In the meantime, the way of reconstruction of membrane-like structure was explored. The establishment of these methods contributes to the reconstructing the whole shape of coal ball plants and relating coal bails to other fossil forms. In addition, the difficulties in three-dimensional reconstruction of coal ball plants by using computer are discussed.