Dataset Information

High-speed shaking of frozen blood clots for extraction of human and malaria parasite DNA.

ABSTRACT:

Background

Frozen blood clots remaining after serum collection is an often disregarded source of host and pathogen DNA due to troublesome handling and suboptimal outcome.

Methods

High-speed shaking of clot samples in a cell disruptor manufactured for homogenization of tissue and faecal specimens was evaluated for processing frozen blood clots for DNA extraction. The method was compared to two commercial clot protocols based on a chemical kit and centrifugation through a plastic sieve, followed by the same DNA extraction protocol. Blood clots with different levels of parasitaemia (1-1,000 p/?l) were prepared from parasite cultures to assess sensitivity of PCR detection. In addition, clots retrieved from serum samples collected within two epidemiological studies in Kenya (n = 630) were processed by high speed shaking and analysed by PCR for detection of malaria parasites and the human ?-thalassaemia gene.

Results

High speed shaking succeeded in fully dispersing the clots and the method generated the highest DNA yield. The level of PCR detection of P. falciparum parasites and the human thalassaemia gene was the same as samples optimally collected with an anticoagulant. The commercial clot protocol and centrifugation through a sieve failed to fully dissolve the clots and resulted in lower sensitivity of PCR detection.

Conclusions

High speed shaking was a simple and efficacious method for homogenizing frozen blood clots before DNA purification and resulted in PCR templates of high quality both from humans and malaria parasites. This novel method enables genetic studies from stored blood clots.

SUBMITTER: Lundblom K

PROVIDER: S-EPMC3171377 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature

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Publications

High-speed shaking of frozen blood clots for extraction of human and malaria parasite DNA.

Lundblom Klara K Macharia Alex A Lebbad Marianne M Mohammed Adan A Färnert Anna A

Malaria journal 20110808

<h4>Background</h4>Frozen blood clots remaining after serum collection is an often disregarded source of host and pathogen DNA due to troublesome handling and suboptimal outcome.<h4>Methods</h4>High-speed shaking of clot samples in a cell disruptor manufactured for homogenization of tissue and faecal specimens was evaluated for processing frozen blood clots for DNA extraction. The method was compared to two commercial clot protocols based on a chemical kit and centrifugation through a plastic si ...[more]

PMID: 21824391

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Project description:The pathogenicity of the malaria parasites results from their ability to invade and remodel red blood cells (RBCs), expressing antigenic variant proteins for immune evasion and survival, and then to egress from the host cell. These sequential processes require concerted actions of a large number of proteins during the intraerythrocytic developmental cycle (IDC)(Boddey and Cowman, 2013; Cowman et al., 2017; Tan and Blackman, 2021), but the molecular basis of the required regulation is only partially understood. Here, we have characterized an essential Apicomplexan AP2 (ApiAP2) transcription factor (we refer to it as PfAP2-MRP; Master Regulator of Pathogenesis) that shows two peaks of expression during the IDC at 16- and 40-hour post-invasion (h.p.i.). When expression of PfAP2-MRP at 40 h.p.i. was disrupted using an inducible gene knockout approach, ∆PfAP2-MRP parasites unable to form mature merozoites and egress from the host RBCs owing to strong down-regulation of several known egress- and invasion-associated genes, in addition to several novel hypothetical genes thought to be involved in these key life cycle processes. Disruption of PfAP2-MRP expression at 16 h.p.i. results in transcriptional activation of the majority of silenced var genes observed at both bulk and single-cell level. This is also reflected by a significantly higher level of immuno-recognition of the exported proteins on the ∆PfAP2-MRP parasite-infected RBCs by pooled sera from malaria-exposed individuals from an endemic region. In addition, overexpression of many early gametocyte marker genes was also observed in ∆PfAP2-MRP parasites at both 40 h.p.i., and at 16 h.p.i. PfAP2-MRP directly regulates these genes by binding to their promoter region or indirectly through 14 other downstream AP2 transcription factors. Taken together, we conclude that PfAP2-MRP is an upstream transcriptional regulator that participates in mutually exclusive expression patterns shown by the var family of genes and is a critical determinant of parasite's growth during the IDC.

Dataset Information

High-speed shaking of frozen blood clots for extraction of human and malaria parasite DNA.

Background

Methods

Results

Conclusions

Publications

High-speed shaking of frozen blood clots for extraction of human and malaria parasite DNA.

Similar Datasets

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