Mutation detection analysis of a region of 16S-like ribosomal RNA gene of Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii

<p>Abstract</p> <p>Background</p> <p>The level of intra-species genetic variation in <it>Entamoeba histolytica, Entamoeba dispar </it>and <it>Entamoeba moshkovskii </it>populations in a localized geographic area, like Puducherry, India, remains unknown.</p> <p>Methods</p> <p>In the present study the existence of genetic variation in the nested multiplex polymerase chain reaction (NM-PCR) amplified region of the 16S-like ribosomal RNA genes of <it>E. histolytica, E. dispar </it>and <it>E. moshkovskii </it>was investigated by riboprinting and single strand conformation polymorphism (SSCP) analysis.</p> <p>Results</p> <p>We found that 70 stool specimens were positive for <it>E. histolytica</it>, 171 stool specimens were positive for <it>E. dispar</it>, and 37 stool specimens were positive for <it>E. moshkovskii </it>by NM-PCR. Ninety liver abscess pus specimens, 21 urine specimens, and 8 saliva specimens were positive for <it>E. histolytica </it>by NM-PCR. Riboprinting analysis detected a mutation in the PCR product of only one <it>E. histolytica </it>isolate from a stool specimen. However, SSCP analysis detected mutations in the PCR products of five <it>E. histolytica </it>isolates and three <it>E. moshkovskii </it>isolates from stool specimens, and one <it>E. histolytica </it>isolate from a saliva specimen. The mutations detected by riboprinting and SSCP analysis were confirmed by sequencing. All the nucleotide sequences showing mutations in this study have already been deposited into the NCBI GenBank database under accession numbers [GenBank: <ext-link ext-link-type="gen" ext-link-id="EF682200">EF682200</ext-link> to GenBank: <ext-link ext-link-type="gen" ext-link-id="EF682208">EF682208</ext-link>].</p> <p>Conclusion</p> <p>The present study has revealed the subsistence of mutations in the ribosomal RNA genes of <it>E. histolytica </it>and <it>E. moshkovskii</it>, which points towards the existence of intra-species genetic variation in <it>E. histolytica </it>and <it>E. moshkovskii </it>isolates infecting humans.</p

Tissue Invasion by Entamoeba histolytica: Evidence of Genetic Selection and/or DNA Reorganization Events in Organ Tropism

Entamoeba histolytica infection may have various clinical manifestations. Nine out of ten E. histolytica infections remain asymptomatic, while the remainder become invasive and cause disease. The most common form of invasive infection is amebic diarrhea and colitis, whereas the most common extra-intestinal disease is amebic liver abscess. The underlying reasons for the different outcomes are unclear, but a recent study has shown that the parasite genotype is a contributor. To investigate this link further we have examined the genotypes of E. histolytica in stool- and liver abscess-derived samples from the same patients. Analysis of all 18 paired samples (16 from Bangladesh, one from the United States of America, and one from Italy) revealed that the intestinal and liver abscess amebae are genetically distinct. The results suggest either that E. histolytica subpopulations in the same infection show varying organ tropism, or that a DNA reorganization event takes place prior to or during metastasis from intestine to liver

Role of Na + -K + ATPase enzyme in vascular response of goat ruminal artery

Objective: To study the role of Na + , K + - ATPase enzyme in the vascular response of goat ruminal artery. Materials and Methods: Ruminal artery was obtained in chilled aerated modified Krebs-Henseleit solution (KHS) from a local slaughterhouse and transported in ice for further processing. The endothelium intact arterial ring was mounted in a thermostatically controlled (37 ± 0.5°C) organ bath containing 20 ml of modified KHS (pH 7.4) bubbled with oxygen (95%) and CO 2 (5%) under 2g tension. An equilibration of 90 min was allowed before addition of drugs into the bath. The responses were recorded isometrically in an automatic organ bath connected to PowerLab data acquisition system. In order to examine intact functional endothelium, ACh (10µM) was added on the 5-HT (1.0µM) - induced sustained contractile response. Similarly, functional characterization of Na + , K + -ATPase activity was done by K + -induced relaxation (10µM-10mM) in the absence and presence of ouabain (0.1µM/ 0.1mM), digoxin (0.1µM) and barium (30µM). Results: ACh (10-5 M) did not produce any relaxing effect on 5-HT-induced sustained contractile response suggesting that vascular endothelium has no significant influence on the activation of sodium pump by extracellular K + in ruminal artery. Low concentration of Ba 2+ (30 µM) (IC 50 : 0.479mM) inhibited K + -induced relaxation suggesting K ir (inward rectifier) channel in part had role in K + -induced vasodilatation in ruminal artery. Vasorelaxant effect of KCl (10µM-10mM) in K + -free medium is also blocked by ouabain (0.1µM and 0.1mM) (IC 50 :0.398mM and IC 35 : 1.36mM), but not by digoxin (0.1µM) (IC 50 0.234mM) suggesting that ouabain sensitive Na + , K + -ATPase isoform is present in the ruminal artery. Conclusion: In the goat ruminal artery functional regulation of sodium pump is partly mediated by K + channel and ouabain sensitive Na + , K + ATPase

Seroprevalence of lymphatic filariasis at Puducherry

Lymphatic filariasis is a major vector borne disease prevalent in the tropics. This study was carried out to estimate the seroprevalence of lymphatic filariasis in and around Puducherry using indirect haemaggulutination test. Of the 5056 clinically suspected cases, 2214 (43.78%) were found to be positive, of whom majority were males (57.8%) belonging to the age group of 21–40 years, indicating that lymphatic filariasis mainly affects the adolescents and adults mainly. This high seroprevalence is a matter of immediate concern and necessary control programme is urgently required to check the transmission of filariasis