Allelic sequence heterozygosity in single Giardia parasites.
Allelic sequence heterozygosity in single Giardia parasites.
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DOI：
10.1186/1471-2180-12-65
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发表时间：
2012-05-03
期刊：
影响因子：
4.2
通讯作者：
Lebbad M
中科院分区：
文献类型：
--
作者：
Ankarklev J;Svärd SG;Lebbad M
遗传异质性已成为肠道原生动物寄生虫肠贾第鞭毛虫基因分型和分子流行病学研究中的一大不便，尤其是对于人类主要的感染基因B集合体。从患者粪便样本中进行基于序列的B集合体B集合体的基因分型，通常由于测序图谱中存在序列异质性而受到阻碍。这可能是由于等位基因序列杂合性(ASH)和/或与不同组合B亚型的寄生虫共同感染所致。因此，出现了两个重要的问题：i)ASH是否发生在单细胞水平，和/或ii)多重亚型感染是否普遍发生在感染B群肠杆菌分离株的患者中？我们用显微操作从病人体内分离出单个肠贾第鞭毛虫、组合B滋养体(GS株)和包囊。来自GS谱系的滋养体TPI基因座的分子分析表明，ASH存在于单细胞水平。对临床样本中BG和TPI位点的B贾第鞭毛虫包囊组合的分析也表明单细胞水平上存在ASH。此外，对来自同一患者的几个不同包囊的序列数据进行比对，得到不同的序列模式，从而表明同一患者中存在与ASH一致的多个亚组装感染。我们的结果最终表明，在B贾第鞭毛虫组合中，ASH确实发生在单细胞水平。此外，在B组合分离株基于序列的基因分型过程中产生的序列异质性可能具有单细胞ASH的复杂性，同时合并不同B组合亚型的感染。这些发现解释了在进行基于序列的集合B贾第虫基因分型时普遍发现的高度序列异质性，并阐明了开发新的肠虫基因分型工具的必要性。
Genetic heterogeneity has become a major inconvenience in the genotyping and molecular epidemiology of the intestinal protozoan parasite Giardia intestinalis, in particular for the major human infecting genotype, assemblage B. Sequence-based genotyping of assemblage B Giardia from patient fecal samples, where one or several of the commonly used genotyping loci (beta-giardin, triosephosphate isomerase and glutamate dehydrogenase) are implemented, is often hampered due to the presence of sequence heterogeneity in the sequencing chromatograms. This can be due to allelic sequence heterozygosity (ASH) and /or co-infections with parasites of different assemblage B sub-genotypes. Thus, two important questions have arisen; i) does ASH occur at the single cell level, and/or ii) do multiple sub-genotype infections commonly occur in patients infected with assemblage B, G. intestinalis isolates? We used micromanipulation in order to isolate single Giardia intestinalis, assemblage B trophozoites (GS isolate) and cysts from human patients. Molecular analysis at the tpi loci of trophozoites from the GS lineage indicated that ASH is present at the single cell level. Analyses of assemblage B Giardia cysts from clinical samples at the bg and tpi loci also indicated ASH at the single cell level. Additionally, alignment of sequence data from several different cysts that originated from the same patient yielded different sequence patterns, thus suggesting the presence of multiple sub-assemblage infections in congruence with ASH within the same patient. Our results conclusively show that ASH does occur at the single cell level in assemblage B Giardia. Furthermore, sequence heterogeneity generated during sequence-based genotyping of assemblage B isolates may possess the complexity of single cell ASH in concurrence with co-infections of different assemblage B sub-genotypes. These findings explain the high abundance of sequence heterogeneity commonly found when performing sequence based genotyping of assemblage B Giardia, and illuminates the necessity of developing new G. intestinalis genotyping tools.
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影响因子：
4
作者：
Lasek-Nesselquist E;Welch DM;Sogin ML
通讯作者：
Sogin ML
影响因子：
12.3
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Brolin KJ;Ribacke U;Nilsson S;Ankarklev J;Moll K;Wahlgren M;Chen Q
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Chen Q
影响因子：
6.4
作者：
Farnert, Anna;Williams, Thomas N.;Marsh, Kevin
通讯作者：
Marsh, Kevin
影响因子：
9.8
作者：
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Bennett RJ
影响因子：
6.7
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Levert M;Zamfir O;Clermont O;Bouvet O;Lespinats S;Hipeaux MC;Branger C;Picard B;Saint-Ruf C;Norel F;Balliau T;Zivy M;Le Nagard H;Cruveiller S;Chane-Woon-Ming B;Nilsson S;Gudelj I;Phan K;Ferenci T;Tenaillon O;Denamur E
通讯作者：
Denamur E