Gold Mineralisation in the Intiédougou Prospect (Diébougou District) in Southwest Burkina Faso, West African Craton

The Intiédougou located in the Houndé Birimian greenstone belt has been the subject of several mining and geoscience studies that have led to the discovery of mineralized gold targets. One of these mineralized targets has prompted work that raises the issue of control factors for the gold mineralization of the prospect. The methodology used in this study combines a study of core drill hole data located in the area and laboratory studies. The Intiédougou sector is based on andesito-basaltic, andesitic interstratified volcanoclastite rocks and Tarkwaïen type detrital sedimentary rocks caught in a vice in the volcano-sedimentary unit. Lithostructural analysis of the sector shows that the subvolcanic rocks bearing gold mineralization are subjected to heterogeneous ductile to brittle deformations and affected by hydrothermalism evolving at stages marked by large fissure fillings. These hydrothermal phases evolve in the zones of expansion created by the brittle deformations that have contributed to the deposits of different types of gold-enriched sulphides. These different phases of hydrothermal destabilization generally of low degree accompany the tardi to post-eburnean brittle tectonics. This deformation system is favorable to the establishment of gold mineralization in the form of vein bodies. The overimposition of deformed and altered areas suggests a genetic relationship between deformation and hydrothermal activity. In conclusion, the mineralization of Intiédougou in vein styles, set up in a volcanic arc environment with a paragenesis of gold-pyrite deposit ± chalcopyrite would be controlled by the structural aspect and accompanied by hydrothermal alteration.

不同施肥类型对蔬菜地土壤抗生素抗性基因和细菌群落结构的影响

农田土壤生态系统是抗生素抗性基因(ARGs)的源与汇,畜禽粪便施用是土壤中ARGs的重要来源。畜禽粪便在蔬菜地土壤中的大量施用,加剧了蔬菜地土壤ARGs的污染,对人类健康造成潜在危害。本文采集了河北省不同施肥类型(施用鲜鸡粪、鲜羊粪、鲜牛粪、商品有机肥以及单施化肥)的蔬菜地表层土壤(0~20cm)样品,采用定量PCR技术和高通量测序技术对蔬菜地土壤ARGs和细菌群落结构开展了研究,旨在探究不同施肥类型蔬菜地土壤中ARGs的分布特征及其影响因素。结果表明,不同施肥类型蔬菜地土壤中均检测到较高丰度的四环素类ARGs(tetA、tetC、tetG、tetL、tetO、tetM、tetW、tetQ)、磺胺类ARGs(sul1、sul2)以及Ⅰ类整合酶基因(intI1),9其中所有施肥处理土壤中磺胺类ARGs总绝对丰度高达9.96×10 copies∙g^(-1)(干土),且显著高于四环素类ARGs总丰9度[1.07×10 copies∙g^(-1)(干土)]。畜禽粪肥和化肥的施用都显著增加了土壤中ARGs丰度,其中高化肥施加量土壤中9 ARGs检出丰度最高[6.34×10 copies∙g^(-1)(干土)],8商品有机肥土壤中ARGs检出丰度最低[3.09×10 copies∙g^(-1)(干土)]。施畜禽粪肥土壤中细菌群落的Shannon指数和Chao1指数显著高于高化肥施加量土壤,但与低化肥施加量土壤差异不显著,说明畜禽粪肥施用显著提高了土壤细菌群落的α多样性。Pearson相关性分析结果表明,细菌群落结构是影响ARGs分布的重要因素。IntI1基因与sul2、tetG、tetQ以及tetW基因呈显著正相关(P<0.05),说明intI1基因在ARGs的传播和扩散中也起着重要作用。本研究结果表明高化肥施用量能显著增加蔬菜地土壤ARGs的丰度,商品有机肥的施用对土壤ARGs丰度影响最小。本研究为评估不同施肥类型蔬菜地土壤中ARGs的污染现状提供了相应的数据参考。

第一类整合酶表达载体的构建及鉴定

Inti1基因是编码整合酶的基因,采用PCR方法对Inti1基因片断进行扩增,扩增子采用Ned1和BamH1双酶切,并克隆到pET19b载体上。把构建好的载体转化至E.coli BL21(DE3)中,在IPTG下进行诱导表达。经SDS-PAGE电泳鉴定以及使用特异性抗His-整合酶单克隆抗体的Western-Bloting证明该重组E.coli BL21(DE3)-Inti1在IPTG诱导下可表达整合酶,此为整合酶表达调控研究奠定了基础。

Integron frequency of Escherichia coli strains from patients with urinary tract infection in Southwest of Iran

Objective: To investigate the frequency of integrase genes intI1, intI2 and intI3 of Escherichia coli strains, and their association with resistance to routinely used antibiotics. Methods: A total of 120 Escherichia coli strains were collected from patients with urinary tract infection in Ahvaz, Southwest of Iran. Antibiotic susceptibility testing was performed. The presence of intI1, intI2, and intI3 genes was determined by polymerase chain reaction. Results: Antibiotic susceptibility testing disclosed the highest resistance rate to ampicillin (91.7%) followed by trimethoprim/sulfamethoxazole (65.8%), and ceftazidime (56.7%). The imipenem susceptibility rate was 91.7%. IntI1 and intI2 were identified in 74 (61.6%) and 8 (6.6%) of Escherichia coli strains, respectively, but intI3 was not found in any isolates. The presence of integrons was significantly associated with resistance to ampicillin, trimethoprim/sulfamethoxazole, ceftazidime, and ciprofloxacin antibiotics (P<0.05). Conclusions: The high resistant Escherichia coli isolates harboring class 1 integrons (intI1) were detected in patients with urinary tract infection in our region. Therefore, preventive strategies are necessary to restrict further dissemination of resistant strains.

华东地区某饮用水源地中磺胺类抗性基因的分布特征

饮用水源中检测到的抗生素抗性基因(antibiotic resistance genes,ARGs)对饮用水质安全和人体健康产生的潜在威胁受到广泛关注.在掌握了华东地区某饮用水源地13种磺胺类抗生素的污染特征基础上,进一步采用定性PCR和荧光定量PCR解析该饮用水源水和底泥中磺胺类ARGs(sul1、sul2)以及抗性基因可转移元件Ⅰ型整合酶基因(int I1)的分布特征.结果表明,3种基因在该饮用水源水和底泥中均100%检出,sul1基因是该饮用水源地中检出含量最高的磺胺类ARGs,在水源水中含量范围为1.5×104~6.4×105copies·mL^(-1),底泥中则高达1.6×108copies·g^(-1),较sul2、int I1基因分别高0.6~2.2、0.5~1.9个数量级.sul1、sul2和int I1基因在该水源地入水口和出水口处的绝对含量无显著差别,而在底泥中sul1、sul2和int I1基因的绝对含量则是出水口高于入水口.sul1在夏季水源地出水口的检出含量最高,为6.4×105copies·mL^(-1);int I1基因在冬季的检出含量高于其他季节.sul1基因与13种磺胺类抗生素具有相关性(r=0.69,P<0.05),其中与磺胺甲唑的含量显著相关(r=0.79,P<0.01);int I1与sul1、sul2的相对含量之间也存在正相关关系(r为0.80和0.73,P<0.05),这表明int I1在磺胺类ARGs的水平转移过程中起到了重要作用.本研究为典型饮用水源地中ARGs的污染现状提供基础数据,也为管控饮用水环境的抗性基因污染和制定管理决策提供依据.

Occurrence and distribution of antibiotic resistance genes in the sediments of the East China Sea bays

The coastal area of the East China Sea has experienced rapid urbanization and industrialization in China since 1980 s, resulting in severe pollution of its environments.Antibiotic resistance genes(ARGs) are regarded as a kind of emerging pollutant with potential high risk. The sediment samples were collected from Hangzhou Bay(HB),Xiangshan Bay(XB), and Taizhou Bay(TB) to investigate the spatial occurrence and distribution of 27 ARGs and class I integron–integrase gene(intI1) in the coastal area of the East China Sea. The PCR results showed the frequent presence of 11 ARGs and intI1 in the sediments of the three bays. The qPCR results further showed that sulfonamide resistance was the most prevalent ARG type and antibiotic target replacement and protection were the most important resistance mechanisms in the sediments. Regarding the subtype of ARGs, sulI, tetW, and dfrA13 were the most abundant ARGs, in which sulI was higher in TB(based on both the absolute and relative abundances) and dfrA13 was higher in HB(based on the relative abundances). The network analysis revealed that intI1 had significant correlations with tetC, sulI, sulII, and blaPSE-1. Oil was the key connected factor, which had positive connections with sulI, sulII, and blaPSE-1. In addition, the joint effect of heavy metals and nutrients & organic pollutants might be crucial for the fate of ARGs in the coastal sediments.

医院污水中大肠埃希菌的耐药谱及Ⅰ类整合子分析

目的调查医院污水中多重耐药菌污染情况及其耐药基因和Ⅰ类整合子携带情况。方法采集河南省郑州大学第一附属医院污水,使用16S rRNA测序和微量生化反应管鉴定细菌种属;采用PCR扩增耐药基因和Ⅰ类整合子基因盒,计算其检出率。结果根据16S测序和生化反应共分离鉴定出23株大肠埃希菌。药敏试验显示23株大肠埃希菌对四环素的耐药率为62.5%(15/23),复方新诺明为56.5%(13/23),氨苄西林为56.5%(13/23)。所有菌株均对美罗培南和亚胺培南敏感。大肠埃希菌多重耐药率为56.52%(13/23)。PCR检测耐药基因携带率aadA1基因为100%,tetA基因为95.8%,aac(6’)-Ib-cr基因为79.2%,CTX基因为70.8%,tetB基因为63.5%,Qnrs基因为58.3%,SHV基因为54.2%,qepA基因为41.7%,Sul基因为35%。所有菌株均不携带KPC基因、IMP基因和NDM1基因。有21株细菌检测到Ⅰ类整合子,其中11株细菌的整合子携带空基因盒。整合子携带的大多数基因盒编码DfrA和aadA基因,有1株细菌的基因盒编码OXA-1基因。结论医院污水中的大肠埃希菌存在多药耐药现象且Ⅰ类整合子携带率高,应引起高度重视。