Assessing Fecal Contamination in Groundwater from the Tulum Region, Quintana Roo, Mexico

The Yucatan Peninsula’s groundwater is experiencing increases in degradation due to swelling population and tourism;yet little is known about sources and transport of contaminants in drinking water supplies. The karst allows for rapid transport of microbial and chemical contaminants to the subsurface, resulting in significantly increased potential for pollution of groundwater. The objective of this research is to determine the occurrence, source, and extent of fecal contamination in the Tulum region of the Peninsula. A multi-analytical approach was undertaken in impacted and unimpacted groundwater locations;measurements included physicochemical parameters, total coliform and E. coli, Bacteroides (human vs total) and caffeine. The results indicate a variation in geochemistry from impacted to protected sites. The total coliform and E. coli show fecal contamination is wide spread. However, the presence of human Bacteriodes and caffeine in the water in the Tulum well field indicates that the recent human activities next to the well field are impacting the drinking water supply. This project is an assessment of the area’s current water quality conditions and the probable impact that the aforementioned growth would have on the area’s water supply. By applying multiple source parameter measurements, including molecular microbiology and chemical indicators it was confirmed the extent of fecal contamination of human origin covered the entire sampling region.

实时荧光定量PCR检测五日热巴通体

目的采用TaqMan- MGB探针建立检测五日热巴通体的实时荧光定量PCR(real- timequantitativePCR)方法。方法根据五日热巴通体特异的16-23SrRNA间隔区序列设计引物和探针,以克隆的1623SrRNA间隔区基因片段作DNA模板,建立了检测五日热巴通体实时荧光定量检测方法。结果建立的定量标准曲线的循环阈值(Ct)与模板拷贝数呈良好的线性关系(r=0.996);与普通PCR相比较,荧光定量PCR检测的灵敏度约为它的200倍。用荧光定量PCR检测其它相关立克次体和细菌,检出结果为阴性。实时荧光定量PCR检测五日热巴通体实验感染小鼠血、脾脏、肝脏和肺组织DNA样本,脾脏和肝脏样本中检出较高水平五日热巴通体DNA,血和肺部检出的目的DNA的水平较低。结论本研究建立的检测五日热巴通体的实时荧光定量PCR法具有很高的检测灵敏度和特异性,可用于临床患者血样本的检测,作五日热的早期诊断。

恒河猴五日热巴尔通体的分离和柠檬酸合成酶基因的序列分析

目的初步研究巴尔通体在恒河猴体内的存在情况,并分析其柠檬酸合成酶(gltA)的基因序列,判断巴尔通体的种属。方法 16只来自福建的恒河猴,用血琼脂培养基分离可能存在的巴尔通体。根据NCBI数据库上的巴尔通体gltA的基因序列,设计一对引物,以巴尔通体菌落为模板进行扩增,将获得的序列进行克隆测序。结果从3只恒河猴体内成功分离到了巴尔通体病原,并获得了巴尔通体gltA全长基因序列,测序结果表明该序列与五日热巴尔通体同源性99%。结论福建来源的恒河猴种群携带巴尔通体病原,巴尔通体流行地区可能存在鼠与灵长类动物之间病原体的流行和传播。

五日热巴通体重组外膜蛋白HbpA的研制和抗原性分析

为克隆并表达五日热巴通体外膜蛋白HbpA的基因,并对其抗原性进行初步分析,采用PCR方法从五日热巴通体基因组DNA扩增hbpA基因,将目的基因片段插入原核表达质粒pET32a(+),构建重组质粒pET32a(+)-hbpA;将构建的重组质粒转化大肠杆菌BL21(DE3)并诱导目的基因表达,以SDS-PAGE电泳以及免疫印迹实验分析表达的目的蛋白。SDS-PAGE电泳分析发现pET32a(+)-hbpA转化菌高效表达一48kDa重组蛋白;免疫印迹分析发现该蛋白与其免疫血清发生强烈反应;间接免疫荧光分析发现该重组蛋白免疫血清能特异识别五日热巴通体。实验结果表明五日热巴通体外膜蛋白HbpA的基因已在大肠杆菌中高效表达。

Experimental-Biological Model of Bartonellosis

Bartonella are known to be important causes ofzooanthroponotic diseases. The range of human infection varies from mild lymphadenopathy and asymptomatic bacteremia to life-threatening systemic disease in immunocompromised patients. Microbiological improvements in isolation methods and PCR amplification of organism-specific DNA sequences have resulted in a dramatic increase in reports describing human patients with bartonellosis. Nevertheless, clearly and successful isolation ofBartonella spp. from bacteremic animals and human patients remains an ongoing challenge. Technology of experimental bartonellosis due to intraperitoneal introduction of biological material samples containing causative agents to laboratory animals is presented in the article. White nonlinear mice with the artificially cyclophosphamide formed immunodeficient state may be used as an experimental model for further investigation of the biological alterations responsible for angiomatosis. On the other hand, we believe that this new method will enhance the diagnostic sensitivity and specificity needed to achieve a diagnosis of bartonellosis.

First record of Leucoagaricus lilaceus(Agaricales:Agaricomycetes)in Mexico

Leucoagaricus lilaceus is recorded for the first time in Mexico.This species is characterized by the purplish pileus,whitish to pinkish gills and a wide bulbose base.The next record represents the northernmost distribution of this species so far in America.Microscopic and macroscopic features are described and illustrated.

Diet variability of snappers(Teleostei:Lutjanidae)in a bay-to-reef ecosystem of the Mexican Caribbean

Fishes use environmental resources differently.Snapper ontogenic movements among coastal habitats lead to diverse diets.We investigated the diets of seven snapper species(Lutjanus apodus,L.analis,L.griseus,L.jocu,L.mahogoni,L.synagris,and Ocyurus chrysurus)in three interconnected coastal environments in the western Caribbean:Río Huach channel,Chetumal/Corozal bay,and the adjacent Xcalak reef lagoon.These three encompass all habitats used by the seven species in the study area.Snapper diets were mostly composed of fish and crustaceans,but dominance of either group varied among the studied habitats;for example,fish were the main prey for L.apodus from the reef lagoon zone,but second in the bay.Snappers are piscivorous-invertivorous mesopredators;the species that relied the most on fishes were L.griseus and L.jocu,whereas O.chrysurus preferred crustaceans.Stomach content results revealed a high degree of dietary overlap among species.Our findings suggested a tradeoff in relative weight between fish and crustaceans as the main food source of snappers at these connected areas,supporting the hypothesis of niche segregation.Our results can be used as a baseline to further our understanding of the ecology and differences in resource use by snapper species in an area undergoing important anthropogenic changes.

中国部分地区实验猕猴巴尔通体感染状况及其遗传特征

【目的】五日热巴尔通体(Bartonella quintana)由体虱在人群中传播,可引起多种人类疾病包括战壕热。为进一步搜集猕猴是五日热巴尔通体自然宿主的证据,本研究调查了国内4个地区实验用猕猴五日热巴尔通体的感染状况,对菌株遗传特征进行了分析。【方法】采集猕猴全血和血清样品各550份,用于菌株分离、核酸和血清IgG抗体检测。应用6个管家基因扩增及测序方法进行菌株鉴定、系统发育及核苷酸多态性分析;应用随机扩增多态性DNA标记(Random amplified polymorphic DNA,RAPD)技术分析不同宿主来源菌株RAPD指纹图谱差异;应用间接免疫荧光法(Indirect immunofluorescence assay,IFA)检测血清中抗五日热巴尔通体IgG抗体水平。【结果】从550只猕猴中分离到8株五日热巴尔通体菌株,带菌率为1.5%;直接PCR检测550份全血核酸的总感染率为8.2%。普通猕猴血清阳性率为19.0%,感染水平明显高于食蟹猕猴(5.6%)。五日热巴尔通体与汉赛巴尔通体RAPD指纹图谱的带型完全不同,猴源和人源五日热巴尔通体菌株Fuller带型基本一致。不同宿主来源菌株核苷酸多态性分析显示,猴源菌株之间差异小,其与人源菌株差异较大。【结论】中国猕猴五日热巴尔通体感染水平较高,普通猕猴自然感染率及抗体水平明显高于食蟹猕猴,猴源与人源菌株的基因型有明显差异。

不明原因发热病人钩端螺旋体和巴尔通体感染调查

目的了解不明原因发热病人钩端螺旋体和巴尔通体的感染状况。方法用显微镜凝集实验方法检测不明原因发热病人血清的钩端螺旋体抗体,用间接免疫荧光法检测血清的汉塞巴尔通体和五日热巴尔通体IgG抗体水平。结果共检测232份不明原因发热病人血清。感染率:汉塞巴尔通体(30.17%)>五日热巴尔通体(18.10%)>钩端螺旋体(4.74%),混合感染率:汉塞巴尔通体和五日热巴尔通体(14.22%)>钩端螺旋体和汉塞巴尔通体(2.16%)>钩端螺旋体和五日热巴尔通体(0.86%),1例病例三项抗体阳性。结论不明原因发热病人中有一定比率的病例是因为感染钩端螺旋体,和/或汉塞巴尔通体、五日热巴尔通体而引起的发热,感染率各不相同,混合感染较为普遍。在不明原因发热的诊断中,有必要进行钩端螺旋体病和巴尔通体病的诊断筛查。