Balderas-Renteria Isaias, García-Lázaro J Francisco, Carranza-Rosales Pilar, Morales-Ramos Lilia H, Galan-Wong Luis J, Muñoz-Espinosa Linda E
Biotechnology Department, Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, Monterrey Nuevo León, Mexico.
Arch Med Res. 2007 May;38(4):372-9. doi: 10.1016/j.arcmed.2007.01.003. Epub 2007 Mar 12.
To understand the molecular basis of virulence variability in Entamoeba histolytica, this study presents results about differential gene expression induced by E. histolytica trophozoites in liver of hamsters in order to produce experimental amebic liver abscess (ALA) and consequently reactivate its virulence.
Amebic cultures were studied before (BALA) and after (AALA) inoculation in hamster peritoneal cavity. Markers of pathogenicity such as the rate of erythrophagocytosis, hemolytic activity, and cytotoxic effects on MDCK cell monolayers were evaluated in order to correlate these phenotypic characteristics to differential gene expression between virulent and non-virulent strains. Genotypic variability was determined by genetic polymorphism using the random-amplified polymorphic DNA (RAPD) technique, which defines the parasite genomic plasticity. mRNA differential display was used in order to identify variable transcripts levels.
The rate of erythrophagocytosis and hemolytic activity were notably increased in AALA in comparison with BALA E. histolytica cultures, as well as the cytotoxic effect on MDCK cells. An increment in the transcription level of several mRNA was shown.
The RAPD technique allowed us to confirm differences in number and size of polymorphic markers bands between virulent and non-virulent stages, suggesting genomic adaptability in E. histolytica. Eight different genes (membrane-bound acid phosphatase, cysteine proteinase, two different ribosomal proteins, heat shock transcription factor, ribosomal RNA, aldehyde dehydrogenase-1 and patatin-like phospholipase) were sequenced and may be associated with a biological function related to the virulence of E. histolytica. Together these findings show genomic variability between virulent and non-virulent cultures of E. histolytica.
为了解溶组织内阿米巴毒力变异性的分子基础，本研究展示了关于溶组织内阿米巴滋养体在仓鼠肝脏中诱导的差异基因表达的结果，以便产生实验性阿米巴肝脓肿（ALA）并因此重新激活其毒力。
对接种于仓鼠腹腔前（BALA）和接种后（AALA）的阿米巴培养物进行研究。评估致病性标志物，如红细胞吞噬率、溶血活性以及对MDCK细胞单层的细胞毒性作用，以便将这些表型特征与有毒和无毒菌株之间的差异基因表达相关联。使用随机扩增多态性DNA（RAPD）技术通过基因多态性确定基因型变异性，该技术定义了寄生虫基因组可塑性。使用mRNA差异显示来鉴定可变转录本水平。
与BALA溶组织内阿米巴培养物相比，AALA中的红细胞吞噬率和溶血活性显著增加，以及对MDCK细胞的细胞毒性作用。显示出几种mRNA转录水平的增加。
RAPD技术使我们能够确认有毒和无毒阶段之间多态性标记带的数量和大小差异，表明溶组织内阿米巴具有基因组适应性。对八个不同基因（膜结合酸性磷酸酶、半胱氨酸蛋白酶、两种不同的核糖体蛋白、热休克转录因子、核糖体RNA、醛脱氢酶-1和类马铃薯Patatin磷脂酶）进行了测序，它们可能与溶组织内阿米巴毒力相关的生物学功能有关。这些发现共同表明溶组织内阿米巴有毒和无毒培养物之间存在基因组变异性。
