The previously analyzed isolates have been cloned using techniques that do not completely assure the source to be from a clonal cell line, FG4592 and unintentional mixing of different in vitro cultures may cause cross-contamination problems when growing cells in microbiological laboratories. Thus, utilization of the micromanipulation

technique rules out the risk of cross contamination since see more downstream analyses are performed on material from a single cell. In order to validate allelic sequence divergence at the single cell level of G. intestinalis, it is of substantial importance to initiate the PCR reaction with high quality template DNA, where DNA from all alleles is present due to the complex nature of the assay. If the sensitivity of the analysis is not high enough, sequences produced in downstream reactions may indicate false negatives where regions of one or several alleles may not be properly amplified and would thereby not display double peaks in the chromatograms. The implementation of DNAreleasy showed full efficiency in

the chromatograms produced from single trophozoites of the GS/M-H7 isolate. A freeze/thaw protocol, which was evaluated simultaneously also produced products in the nested PCR reaction in accordance selleck compound with Miller et al [19]. This method however, only produced one sequence out of five that allowed the discrimination of double peaks in the chromatograms (Table 1). The in vitro establishment

of viable assemblage B cysts (GS isolate) is highly inefficient Forskolin nmr (unpublished data), and therefore impeded the addition of a proper control for the purpose of verifying the presence of ASH in sequences generated from single Giardia cysts. DNAreleasy for DNA extraction was the only method sensitive enough to generate sequences where ASH could be detected when analyzing single trophozoites, therefore, two different DNAreleasy protocols provided by the manufacturer were assayed on the clinical cysts. Utilization of the long protocol indicated a higher proficiency in downstream PCR reactions (data not shown). ASH was seen on the single cell level in all DNAreleasy treated single cells of the GS/M isolate, thus verifying our hypothesis of the occurrence of ASH in single Giardia assemblage B parasites. Positions in the sequence on the tpi locus, that have earlier been highlighted as variable between different sub-assemblages or haplotypes of GS/M (Table 1) were here verified as double peaks, indicating sequence divergence in the different alleles in single Giardia cells. ASH also occurred at the single cell level in the majority of the cysts (21 out of 36 analyzed assemblage B cysts). However, the alignment of all sequences from a single patient sample did not result in the establishment of a consensus sequence.