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991.
992.
土壤反硝化对磺胺嘧啶及抗性基因消减的影响 总被引:1,自引:0,他引:1
农田土壤中抗生素及抗性基因的复合污染已给生态环境安全和人体健康带来了全新隐患。针对厌氧条件下,反硝化作用过程对土壤抗生素乃至抗性基因消减影响的研究一直相对较少。因而,本研究采集牛粪堆积池塘周边底层农田土壤作为目标污染土壤,重点研究反硝化作用过程对土壤磺胺嘧啶及抗性基因消减动态的影响。结果表明:相较于原始污染土壤处理(T1),添加了NO_3~–-N的处理(T2)可以显著强化土壤和水相中反硝化速率,提升N_2O的产气速率,促进土壤中磺胺嘧啶浓度和抗性基因丰度的快速降低;同时发现土壤反硝化基因(nir K、nir S和nos Z)与磺胺类抗性基因(sul Ⅰ和sul Ⅱ)呈显著负相关(P0.05),说明当NO_3~–-N底物越充足,土壤反硝化细菌活性往往被激活,其反硝化功能基因表达就越活跃,土壤反硝化作用过程就越强烈,从而反馈作用促进磺胺嘧啶抗生素的厌氧消减,进而有助于sul系列抗性基因丰度的显著衰减;同时通过高通量测序技术及对反硝化细菌的分离筛选后,发现变形菌门(Proteobacteria)赖氨酸芽胞杆菌属(Lysinibacillus)的细菌是土壤厌氧反应前后的主导优势菌群,对于强化反硝化过程和促进磺胺嘧啶及sul抗性基因的消减发挥了潜在的积极作用。本研究结果可为探明土壤中抗生素的厌氧消减过程和缓解抗性基因的扩散传播提供新颖的认知基础。 相似文献
993.
Huaisong WANG Rui GUO Yibo TIAN Nan CUI Xinxin WANG Lei WANG Zhongbao YANG Shuying LI Jixun GUO Lianxuan SHI Tao ZHANG 《土壤圈》2024,34(2):497-507
Ammonia (NH3) emissions, the most important nitrogen (N) loss form, always induce a series of environmental problems such as increased frequency of regional haze pollution, accelerated N deposition, and N eutrophication. Arbuscular mycorrhizal (AM) fungi play key roles in N cycling. However, it is still unclear whether AM fungi can alleviate N losses by reducing NH3 emissions. The potential mechanisms by which AM fungi reduce NH3 emissions in five land-use types (grazed grassland, mowed grassland, fenced grassland, artificial alfalfa grassland, and cropland) were explored in this study. Results showed that AM fungal inoculation significantly reduced NH3 emissions, and the mycorrhizal responses of NH3 emissions were determined by land-use type. Structural equation modeling (SEM) showed that AM fungi and land-use type directly affected NH3 emissions. In addition, the reduction in NH3 emissions was largely driven by the decline in soil NH+4-N and pH and the increases in abundances of ammonia-oxidizing archaea (AOA) amoA and bacteria (AOB) amoB genes, urease activity, and plant N uptake induced by AM fungal inoculation and land-use type. The present results highlight that reducing the negative influence of agricultural intensification caused by land-use type changes on AM fungi should be considered to reduce N losses in agriculture and grassland ecosystems. 相似文献
994.
995.
番茄细菌性叶斑病是由Pseudomonas syringae pv. tomato引起的一种世界范围内广泛发生的植物细菌性病害,其模式菌株DC3000已完成全基因组测序。试验通过比较基因组学方法将该模式菌株基因组中的致病基因与其他已完成全基因组测序的植物病原细菌的基因组序列进行比对,得到3个DC3000菌株特有的致病基因PSPTO_4707、PSPTO_4708、PSPTO_4711,并对PSPTO_4711基因进行原核表达和蛋白活力检测,发现其表达的活性蛋白对拟南芥具有很强的毒性。 相似文献
996.
[目的]构建CBHⅡ基因过量表达的绿色木霉工程菌。[方法]根据绿色木霉cDNA序列设计合成引物,PCR扩增CBHⅡ基因序列,将完整的目的基因与表达载体pCAMBIA1302连接,转入大肠杆菌DH5α中,获得重组质粒pCAMBIA1302-CBHⅠ。再将pCAM-BIA1302-CBHⅠ重组质粒与瑞氏木霉外切葡聚糖纤维二糖水解酶Ⅱ(CBHⅡ)PcbhⅡ启动子片段连接,将潮霉素磷酸转移酶(hyg)基因片段插入PcbhⅡ启动子下游,转入大肠杆菌DH5α中,获得重组表达质粒pCAMBIA1302-CBHⅡ。[结果]构建的重组表达质粒电转化后经SDS-PAGE电泳检测,绿色木霉纤维素酶CBHII基因在原宿主菌中成功过量表达,证实CBHⅡ基因在PcbhⅡ启动子控制下进行高效表达。[结论]为高产纤维素酶系的工业化菌株构建奠定基础。 相似文献
997.
998.
Luis Varona 《Zeitschrift für Tierzüchtung und Züchtungsbiologie》2010,127(1):16-25
After quantitative trait loci (QTL) detection, one of the main objectives of research is to identify the causal mutation explaining phenotypic differences. Candidate genes are usually selected according to the physiological mechanism of the trait and their location within the same region of the QTL. After detection of any polymorphism at the candidate gene sequence, it is important to determine whether the detected mutation is the one that causes the phenotypic variation. This is not, however, an easy task, because of the linkage disequilibrium between the genes located in the same region. Several methods have been proposed that consider the neutral marker information in validating the involvement of candidate genes. However, some statistical information may be lost because of the presence of both the QTL and candidate gene effects in the model of analysis. Here, the Bayes factor is suggested as an alternative and a procedure for its calculation between candidate gene and QTL models is presented. The procedure is illustrated with a simulation study and with an example consisting of three SNPs detected at the leptin receptor (LEPR) in an experimental intercross between Iberian and Landrace pigs. The results indicate that the Bayes factor procedure is more powerful than the classical approach. 相似文献
999.
AMP激活的蛋白激酶(AMP-activated prorein kinase,AMPK)是一种能被腺苷一磷酸(AMP)激活的蛋白激酶。在动物应激(生理、营养、环境和疾病等)过程中起着重要作用。近年研究表明,AMPK在细胞和全身组织器官能量代谢平衡中起着举足轻重的作用,并且在调节物质代谢中起重要作用,其调节代谢过程主要包括葡萄糖转换,糖酵解和脂类代谢等。近年来在牛上已经进行了很多研究,其中包括其染色体定位及结构的确定等。本文将简要介绍AMPK的分子结构及功能,并对AMPK基因在牛上的研究进展进行综述。 相似文献
1000.
Dragutin Perina Marina Korolija Marijana Popovi? Had?ija Ivana Grbe?a Robert Belu?i? Mirna Ime?ek Christine Morrow Melanija Posavec Marjanovi? Tatjana Bakran-Petricioli Andreja Miko? Helena ?etkovi? 《Marine drugs》2015,13(7):4179-4196
Finkel-Biskis-Reilly murine sarcoma virus (FBR-MuSV) ubiquitously expressed (FAU) gene is down-regulated in human prostate, breast and ovarian cancers. Moreover, its dysregulation is associated with poor prognosis in breast cancer. Sponges (Porifera) are animals without tissues which branched off first from the common ancestor of all metazoans. A large majority of genes implicated in human cancers have their homologues in the sponge genome. Our study suggests that FAU gene from the sponge Suberites domuncula reflects characteristics of the FAU gene from the metazoan ancestor, which have changed only slightly during the course of animal evolution. We found pro-apoptotic activity of sponge FAU protein. The same as its human homologue, sponge FAU increases apoptosis in human HEK293T cells. This indicates that the biological functions of FAU, usually associated with “higher” metazoans, particularly in cancer etiology, possess a biochemical background established early in metazoan evolution. The ancestor of all animals possibly possessed FAU protein with the structure and function similar to evolutionarily more recent versions of the protein, even before the appearance of true tissues and the origin of tumors and metastasis. It provides an opportunity to use pre-bilaterian animals as a simpler model for studying complex interactions in human cancerogenesis. 相似文献